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Dehydroepiandrosterone (DHEA) treatment in vitro inhibits adipogenesis in human omental but not subcutaneous adipose tissue
Abstract
Dehydroepiandrosterone (DHEA), a precursor sex steroid, circulates in sulphated form (DHEAS). Serum DHEAS concentrations are inversely correlated with metabolic syndrome components and in vivo/in vitro studies suggest a role in modulating adipose mass. To investigate further, we assessed the in vitro biological effect of DHEA in white (3T3-L1) and brown (PAZ6) preadipocyte cell lines and human primary preadipocytes. DHEA (from 10(-8)M) caused concentration-dependent proliferation inhibition of 3T3-L1 and PAZ6 preadipocytes. Cell cycle analysis demonstrated unaltered apoptosis but indicated blockade at G1/S or G2/M in 3T3-L1 and PAZ6, respectively. Preadipocyte cell-line adipogenesis was not affected. In human primary subcutaneous and omental preadipocytes, DHEA significantly inhibited proliferation from 10(-8)M. DHEA 10(-7)M had opposing effects on adipogenesis in the two fat depots. Subcutaneous preadipocyte differentiation was unaffected or increased whereas omental preadipocytes showed significantly reduced adipogenesis. We conclude that DHEA exerts fat depot-specific differences which modulate body composition by limiting omental fat production.
... In vitro studies have shown that DHEA inhibits proliferation and differentiation of adipocytes [16,32,33]. In cultured human omental and subcutaneous preadipocytes, DHEA added at physiological concentrations suppressed cell proliferation [32]. ...
... In vitro studies have shown that DHEA inhibits proliferation and differentiation of adipocytes [16,32,33]. In cultured human omental and subcutaneous preadipocytes, DHEA added at physiological concentrations suppressed cell proliferation [32]. DHEA also inhibited the proliferation of 3T3-L1 and 3T3-F442A preadipocytes, and the authors suggested that DHEA may act on adipocyte proliferation by activation of androgen receptor [16]. ...
... DHEA also inhibited the proliferation of 3T3-L1 and 3T3-F442A preadipocytes, and the authors suggested that DHEA may act on adipocyte proliferation by activation of androgen receptor [16]. Moreover, treatment with DHEA inhibited the differentiation of human omental preadipocytes [32]. This effect was not observed in human subcutaneous fat cells [32]. ...
Dehydroepiandrosterone (DHEA) and its sulfate ester, DHEAS, are the major circulating adrenal steroids and serve as substrates for sex hormone biosynthesis. DHEA is effectively taken up by adipose tissue, where the concentrations of free DHEA are four to ten times higher than those found in the circulation. DHEA reduces adipose tissue mass and inhibits the proliferation and differentiation of adipocytes; it may also protect against obesity by lowering the activity of stearoyl-CoA desaturase 1 in fat cells. Recent studies demonstrate that DHEA stimulates triacylglycerol hydrolysis in adipose tissue by increasing the expression and activity of adipose triglyceride lipase and hormone-sensitive lipase, the key enzymes of lipolysis. DHEA has been shown to modulate insulin signaling pathways, enhance glucose uptake in adipocytes, and increase insulin sensitivity in patients with DHEA deficiency or abnormal glucose tolerance. Additionally, by suppressing the activity of 11β-hydroxysteroid dehydrogenase 1 in adipocytes, DHEA may promote intra-adipose inactivation of cortisol to cortisone. Several studies have demonstrated that DHEA may also regulate the expression and secretion of adipokines such as leptin, adiponectin, and resistin. The effects of DHEA on adipokine expression in adipose tissue are depot-specific, with visceral fat being the most responsive. The mechanisms underlying DHEA actions in adipose tissue are still unclear; however, they involve nuclear receptors such as androgen receptor and peroxisome proliferator-activated receptors γ and α. Because clinical trials investigating the effects of DHEA failed to yield consistent results, further studies are needed to clarify the role of DHEA in the regulation of human adipose tissue physiology.
... In agreement with two other studies on the effects of the steroid hormone dehydroepiandrosterone (DHEA) on human pre-adipocytes, the proliferation of PAZ6 cells, tested in parallel with 3T3-L1 and human primary pre-adipocytes, was significantly inhibited (Rice et al., 2010). The effect was observed in both cell lines under a 24 h exposure of 100 nM to 100 μM DHEA. ...
... The effect was observed in both cell lines under a 24 h exposure of 100 nM to 100 μM DHEA. Intraadipocyte DHEA concentration is an order of magnitude higher than the circulating levels which are within the nanomolar range, so the concentrations used in those test were within physiological levels (Rice et al., 2010). ...
... Some of these components are yet to be uncovered. Zilberfarb et al. (1997) Multilocular fat accumulation Zilberfarb et al. (1997) β 3 -AR predominance Jockers et al. (1998) PAZ6 ADIPOSE FEATURES aP2, PPARγ, C/EBP-α, HSL, LPL, leptin, GLUT1, and GLUT4 presence Zilberfarb et al. (1997) β 1 , β 2 , and β 3 -AR expression and β-adrenergic-coupled lipolysis Zilberfarb et al. (1997) PPARγ-sensitive differentiation Strobel et al. (1999) Melatonin receptor expression (isoform MT2, found in BAT) Brydon et al. (2001) OTHER PAZ6 FEATURES Transfectable Oberkofler et al. (2002Oberkofler et al. ( , 2004a Anti-proliferative response to DHEA Rice et al. (2010) A human brown adipose cell model, such as the PAZ6 cells, could become an essential tool to address these relevant questions: what conditions contribute to persistence of the "BAT-like" phenotype or protection from apoptosis? What factors stimu-late nutrient catabolism and subsequent UCP1-mediated proton leak? ...
... Rodent adrenals lack the ability to synthesize DHEA, and the validity of these findings to human physiology is questionable. Recently, it was shown that DHEA inhibits proliferation in PAZ6 preadipocytes, a cell line derived from human brown adipose tissue, and adipogenesis in omental but not subcutaneous preadipocytes (39), highlighting possible depot-specific effects of DHEA. However, human in vivo trials have proved less conclusive, and human in vitro studies are limited (44). ...
... More recently, it was shown that DHEA reduces body weight and epididymal fat in a murine model of obese type 2 diabetes (18). Interestingly, it was shown that although DHEA does not affect differentiation of human primary subcutaneous preadipocytes, it has inhibitory effects on proliferation and differentiation of omental preadipocytes (39). However, all of these previous studies have failed to provide clear mechanistic insights into the effects of DHEA. ...
... Our observation that DHEA results in preadipocyte proliferation through arrest in the G1 phase of the cell cycle is consistent with earlier murine studies utilizing 3T3-L1 cells (20,32,34) and human preadipocytes (39). This effect is in contrast to glucocorticoids, which are known to stimulate subcutaneous preadipocyte proliferation in a depot-specific manner (3). ...
Glucocorticoids increase adipocyte proliferation and differentiation, a process underpinned by the local reactivation of inactive cortisone to active cortisol within adipocytes, catalyzed by 11β-hydroxysteroid dehydrogenase type (11β-HSD1). The adrenal sex steroid precursor dehydroepiandrosterone (DHEA) has been shown to inhibit 11β-HSD1 in murine adipocytes; however, rodent adrenals do not physiologically produce DHEA. Here we aimed to determine the effects and underlying mechanisms of the potential anti-glucocorticoid action of DHEA and its sulfate ester DHEAS in human preadipocytes. Utilizing a human subcutaneous preadipocyte cell line, Chub-S7, we examined the metabolism and effects of DHEA in human adipocytes, including adipocyte proliferation, differentiation, 11β-HSD1 expression and activity and glucose uptake. DHEA, but not DHEAS, significantly inhibited preadipocyte proliferation via cell cycle arrest in G1 phase, independent of sex steroid and glucocorticoid receptor activation. 11β-HSD1 oxoreductase activity in differentiated adipocytes was inhibited by DHEA. DHEA co-incubated with cortisone significantly inhibited preadipocyte differentiation, assessed by the expression of markers of early (LPL) and terminal (G3PDH) adipocyte differentiation. Co-incubation with cortisol, negating the requirement for 11β-HSD1 oxoreductase activity, diminished the inhibitory effect of DHEA. Further consistent with glucocorticoid-opposing effects of DHEA, insulin-independent glucose uptake was significantly enhanced by DHEA treatment. DHEA increases basal glucose uptake and inhibits human preadipocyte proliferation and differentiation, thereby exerting an anti-glucocorticoid action. DHEA inhibition of the amplification of glucocorticoid action mediated by 11β-HSD1 contributes to the inhibitory effect of DHEA on human preadipocyte differentiation.
... Adipogenesis was induced in confluent cells by replacing with differentiation medium [adipogenic medium (ADM)] containing 10% FCS, biotin (33μM), panthothenate (17μM), T3 (1nM), dexa-methasone (100nM), thiazolidinedione (TZD) (1μM), and insulin (500nM) for 22 days, adipogenesis was assessed by microscopic examination to detect the characteristic morphological changes (cell rounding, accumulation of lipid drop lets), acquisition of lipid filled droplets [oil red O (ORO) stain ing], and transcript measurement of adipogenic markers (PPARγ, LPL) by qPCR as described previously(16). In addition, foci of differentiation (groups of cells with lipid droplets) were counted in 10 different fields for each experimental condition(36). ...
... Preadipocyte/fibroblasts were obtained by collagenase digest, as previously described(36). Cells were used at low passage number (<5); hence, not all samples were analyzed in all experiments. ...
Evidence from clinical and experimental data suggests that thyrotropin receptor (TSHR) signaling is involved in energy expenditure through its impact on white adipose tissue (WAT) and brown adipose tissue (BAT). TSHR expression increases during mesenchymal stem cell (MSC) differentiation into fat. We hypothesize that TSHR activation [TSHR*, elevated thyroid-stimulating hormone, thyroid-stimulating antibodies (TSAB), or activating mutation] influences MSC differentiation, which contributes to body composition changes seen in hypothyroidism or Graves’ disease (GD). The role of TSHR activation on adipogenesis was first investigated using ex vivo samples. Neck fat (all euthyroid at surgery) was obtained from GD (n = 11, TSAB positive), toxic multinodular goiter (TMNG, TSAB negative) (n = 6), and control patients with benign euthyroid disease (n = 11, TSAB negative). The effect of TSHR activation was then analyzed using human primary abdominal subcutaneous preadipocytes (n = 16). Cells were cultured in complete medium (CM) or adipogenic medium [ADM, containing thiazolidinedione (TZD), PPARγ agonist, which is able to induce BAT formation] with or without TSHR activation (gain-of-function mutant) for 3 weeks. Adipogenesis was evaluated using oil red O (ORO), counting adipogenic foci, qPCR measurement of terminal differentiation marker (LPL). BAT [PGC-1α, uncoupling protein 1 (UCP1), and ZIC1], pre-BAT (PRDM16), BRITE− (CITED1), or WAT (LEPTIN) markers were analyzed by semiquantitative PCR or qPCR. In ex vivo analysis, there were no differences in the expression of UCP1, PGC-1α, and ZIC1. BRITE marker CITED1 levels were highest in GD followed by TMNG and control (p for trend = 0.009). This was associated with higher WAT marker LEPTIN level in GD than the other two groups (p < 0.001). In primary cell culture, TSHR activation substantially enhanced adipogenesis with 1.4 ± 0.07 (ORO), 8.6 ± 1.8 (foci), and 5.5 ± 1.6 (LPL) fold increases compared with controls. Surprisingly, TSHR activation in CM also significantly increased pre-BAT marker PRDM16; furthermore, TZD-ADM induced adipogenesis showed substantially increased BAT markers, PGC-1α and UCP1. Our study revealed that TSHR activation plays an important role in the adipogenesis process and BRITE/pre-BAT formation, which leads to WAT or BAT phenotype. It may contribute to weight loss as heat during hyperthyroidism and later transforms into WAT posttreatment of GD when patients gain excess weight.
... Using cell lines, it was demonstrated that DHEA has inhibitory effects on murine 3T3-L1 preadipocyte proliferation, differentiation, and lipid accumulation [38,48,51,52]. In addition, DHEA had distinct effects in adipogenesis from brown or white omental versus subcutaneous adipose human-derived cells, with reduced in the former and no effect in the latter [51], indicating the depot-specific effects of DHEA. ...
... Using cell lines, it was demonstrated that DHEA has inhibitory effects on murine 3T3-L1 preadipocyte proliferation, differentiation, and lipid accumulation [38,48,51,52]. In addition, DHEA had distinct effects in adipogenesis from brown or white omental versus subcutaneous adipose human-derived cells, with reduced in the former and no effect in the latter [51], indicating the depot-specific effects of DHEA. Furthermore, in young female Wistar rats, 0.6% DHEA for 9 weeks induced higher lipolysis rate in isolated adipocytes as well as the reduced fat pads weights [49]. ...
Dehydroepiandrosterone (DHEA), mostly present as its sulfated ester (DHEA-S), is an anabolic hormone that naturally declines with age. Furthermore, it is the most abundant androgen and estrogen precursor in humans. Low plasma levels of DHEA have been strongly associated with obesity, insulin resistance, dyslipidemia, and high blood pressure, increasing the risk of cardiovascular disease. In this respect, DHEA could be regarded as a promising agent against metabolic syndrome (MetS) in postmenopausal women, since several age-related metabolic diseases are reported during aging. There are plenty of experimental evidences showing beneficial effects after DHEA therapy on carbohydrate and lipid metabolism, as well as cardiovascular health. However, its potential as a therapeutic agent appears to attract controversy, due to the lack of effects on some symptoms related to MetS. In this review, we examine the available literature regarding the impact of DHEA therapy on adiposity, glucose metabolism, and the cardiovascular system in the postmenopausal period. Both clinical studies and in vitro and in vivo experimental models were selected, and where possible, the main cellular mechanisms involved in DHEA therapy were discussed.
Schematic representation showing some of the general effects observed after administration DHEA therapy on target tissues of energy metabolism and the cardiovascular system. ↑ represents an increase, ↓ represents a decrease, – represents a worsening and ↔ represents no change after DHEA therapy
... Dose dependent effects of androgens on the proliferation of preadipocytes, no effects at low concentration 28 and inhibitory at high concentrations 33 , are reported. Androgens have been shown to consistently inhibit adipogenesis in multiple cell types including human preadipocytes in vitro 34,35 and hence, through this mechanism androgens could reduce fat mass. The expression levels of AR mRNA and androgen binding capacity are higher in intraabdominal than subcutaneous depots 36,37 and androgen-mediated suppression of adipogenesis is more pronounced in preadipocytes isolated from omental than subcutaneous adipose tissues. ...
... The expression levels of AR mRNA and androgen binding capacity are higher in intraabdominal than subcutaneous depots 36,37 and androgen-mediated suppression of adipogenesis is more pronounced in preadipocytes isolated from omental than subcutaneous adipose tissues. 34,35 Through this depot-specific inhibition of adipogenesis, androgens may preferentially reduce VAT. Mixed results are however, reported whether androgen treatment leads to preferential loss of abdominal or visceral adiposity in humans. ...
Men and women are different in their fat mass and distribution pattern. The gynoid-type fat distribution, accumulation in lower-body, is considered to be protective while the android-type accumulation in upper-body, both in abdominal subcutaneous and visceral depots, is detrimental. Sex-dependent depot differences in adipose metabolic and endocrine functions are thought to contribute to the sexual disparity in fat distribution as well as its association with cardiometabolic risks. Although molecular details have not been completely elucidated, available evidence shows that sex steroid hormones are important factors governing sexual dimorphism in adipose tissue distribution and hence, risks for metabolic diseases. We will review sex-dependent heterogeneities in adipose tissue properties that can link their depot-specific biology to metabolic complications in men and women. In addition, we will also review how sex steroids regulate adipose tissue biology, both development and functional characteristics, with emphasis on their depot-dependent actions.
... In vitro effects are controversial; antiadipogenic in 3T3-L1 and human ASCs (189), no effects in 3T3-L1 cells (277,390), proadipogenic in rat ASCs isolated from female, but not male, intra-abdominal depot (77) Ovariectomy increases, while estrogen treatment decreases fat mass and adipocyte size in rodents (63,208) Depot-specific effects, reduction of intra-abdominal depots without significant effects in inguinal depots, are noted (63) Both global and adipose ERα knockout mice develop obesity (68,207) Androgen Antiadipogenic in 3T3-L1, 10T1/2 cell lines (337), rat ASCs (77), human MSCs, and human ASCs (122) Antiadipogenic effects are more pronounced in ASCs from intra-abdominal depots (77,122,302) Male AR knockout mice develop late-onset obesity but female AR knockout mice are not affected (87,324) Adipose-specific AR knockout mice exhibit no changes in adiposity when fed chow (422), but develop obesity when fed HFD (229) In males, controversial effects of androgen supplementation on adiposity are reported in both rodents and humans (7,122,185,223,249) In females, androgen excess is associated with central obesity (254) Thyroid hormone Proadipogenic in brown adipocyte cell line (235) and 3T3-L1 cells (239) No significant impairment of adipose tissue development in both DIO2 knockout (128) and TRα1-/-β-/-knockout mice (112) Vitamin D In vitro effects are controversial; anti-adipogenic in 3T3-L1 (30,181), proadipogenic in mouse and human ASC cultures (253,258) 1α-hydroxylase and VDR knockout mice have reduced fat mass (252,409), whereas VDR overexpressing transgenic mice contain more adipose mass (408) Vitamin A/retinoids RA: depending on doses and time-points of treatment either antiadipogenic or proadipogenic in 3T3-L1 (297) and Ob17 and rat ASCs (315) Retinaldehyde: antiadipogenic in 3T3-L1 cells (433) ALDH1A1 null mice are lean (297) and protected from HFD-induced obesity (433), whereas RDH1 null mice develop obesity (429) Sex-dependent reduction of intra-abodminal fat in ALDH1A1 knockout mice (143) Leptin ...
... In cell culture models, androgeninhibition of adipogenesis is reported to be greater in visceral and subcutaneous ASCs. DHEA has been shown to inhibit adipogenesis in human omental, but not subcutaneous ASCs (302). The antiadipogenic effects of DHT are more Proliferation Differentiation ...
Adipose tissue includes multiple anatomical depots that serve as an energy reserve that can expand or contract to maintain metabolic homeostasis. During normal growth and in response to overnutrition, adipose tissue expands by increasing the volume of preexisting adipocytes (hypertrophy) and/or by generating new adipocytes (hyperplasia) via recruitment and differentiation of adipose progenitors. This so-called healthy expansion through hyperplasia is thought to be beneficial in that it protects against obesity associated metabolic disorders by allowing for the “safe” storage of excess energy. Remodeling adipose tissue to replace dysfunctional adipocytes that accumulate with obesity and age also requires new fat cell formation and is necessary to maintain metabolic health. Adipogenesis is the process by which adipose progenitors become committed to an adipogenic lineage and differentiate into mature adipocytes. This transition is regulated by complex array of transcriptional factors and numerous autocrine, paracrine, and endocrine signals. We will focus on hormonal factors that regulate adipocyte differentiation and their molecular mechanisms of actions on adipogenesis as studied in vitro and in vivo. Accumulating evidence indicates that adipose progenitors isolated from different adipose tissues exhibit intrinsic differences in adipogenic potential that may contribute to the depot and sex differences in adipose expansion and remodeling capacity. We will put special emphasis on the hormonal factors that are known to depot-dependently affect body fat accumulation and adipocyte development. © 2017 American Physiological Society. Compr Physiol 7:1151-1195, 2017.
... It was demonstrated that 17, 20 lyase and 3β-HSD II activities can be affected by adipose tissue, fat distribution, and glucose/insulin balance (30)(31)(32)(33)(34)44). Putative mechanisms may involve growth factors, insulin, cytokines, free fatty acids, and inflammatory markers (44). ...
... The concern with imprecise androgen measurement seems not to be justified because comparisons of the results between the assays used in the current study for T, 17-OHPE, 17-OHP4, and compound S and liquid chromatography tanden mass spectrometry have shown good agreement between the methods(28,29).Some adipocyte-derived products may induce the transcription of the StAR promoter protein and modulate steroidogenic enzyme activities(30,31). On the other hand, DHEA has shown antiadipogenic activity on adipocyte cells with capability of improving adipocyte insulin sensitivity and improve adipokine profile(32). In the present study, besides correlating with DHEA, the concentrations of 17-OHPE showed different relationship with several anthropometric and metabolic parameters in normo and hyperandrogenemic PCOS patients. ...
Objective:
To examine the anthropometric, and metabolic connections of 17-hydroxypregnenolone in the normo- and hyperandrogenemic polycystic ovary syndrome phenotypes.
Material and methods:
This cohort study enrolled 91 normal cycling healthy women, 46 normoandrogenemic and 147 hyperandrogenemic patients with polycystic ovary syndrome (PCOS). Anthropometric, biochemical, and hormonal parameters were properly verified and correlated with 17-hydroxypregnenolone (17-OHPE) concentrations.
Results:
17-OHPE was higher in hyperandrogenemic PCOS than in normoandrogenemic PCOS and control groups (p= 0.032 and p <0.001, respectively). In healthy controls, 17-OHPE was positively associated with glucose, free estrogen index, DHEAS and negatively associated with compounds S. In normoandrogenemic PCOS patients 17-OHPE presented positive correlation with VAI (r= 0.365, p= 0.011), LAP (r= 0.318 p= 0.043), cortisol (r= 0.311, p= 0.048), insulin (r= 0.414, p= 0.008), and HOMA-IR (r=0.408, p= 0.011). In the hyperandrogenemic group, 17-OHPE presented significant negative correlation with most anthropometric parameters, HOMA-IR, HOMA % B, estradiol, FEI, C-peptide, and TG levels, and positive correlation with HOMA-S and high-density lipoprotein cholesterol (HDL-c), sex-hormone binding globulin (SHBG), androstenedione (A4), and dehydroepiandrosterone (DHEA). Regarding hyperandrogenemic PCOS, and using a stepwise multiple regression, only HOMA-S and WHR were retained in the model (R2 = 0.294, p < 0.001).
Conclusion:
17-OHPE exhibited different relationships with anthropometric, and biochemical parameters in PCOS patients, depending on the androgen levels. In PCOS subjects with high androgen concentrations 17-OHPE was negatively associated with most anthropometric parameters, particularly with those used as markers of adipose tissue dysfunction and frequently employed as predictors of cardiovascular disease risk; otherwise, 17-OHPE was positively associated with HDL-C and HOMA-S in this patients. Future studies are required to evaluate the clinical implications of these novel findings.
... Preadipocyte/fibroblasts were obtained by collagenase digest, as previously described (36). Cells were used at low passage number (<5); hence, not all samples were analyzed in all experiments. ...
... Adipogenesis was induced in confluent cells by replacing with differentiation medium [adipogenic medium (ADM)] containing 10% FCS, biotin (33μM), panthothenate (17μM), T3 (1nM), dexa-methasone (100nM), thiazolidinedione (TZD) (1μM), and insulin (500nM) for 22 days, adipogenesis was assessed by microscopic examination to detect the characteristic morphological changes (cell rounding, accumulation of lipid drop lets), acquisition of lipid filled droplets [oil red O (ORO) stain ing], and transcript measurement of adipogenic markers (PPARγ, LPL) by qPCR as described previously(16). In addition, foci of differentiation (groups of cells with lipid droplets) were counted in 10 different fields for each experimental condition(36). ...
Evidence from clinical and experimental data suggests that thyrotropin receptor (TSHR) signaling is involved in energy expenditure through its impact on white adipose tissue (WAT) and brown adipose tissue (BAT). TSHR expression increases during mesenchymal stem cell (MSC) differentiation into fat. We hypothesize that TSHR activation [TSHR*, elevated thyroid-stimulating hormone, thyroid-stimulating antibodies (TSAB), or activating mutation] influences MSC differentiation, which contributes to body composition changes seen in hypothyroidism or Graves’ disease (GD). The role of TSHR activation on adipogenesis was first investigated using ex vivo samples. Neck fat (all euthyroid at surgery) was obtained from GD (n = 11, TSAB positive), toxic multinodular goiter (TMNG, TSAB negative) (n = 6), and control patients with benign euthyroid disease (n = 11, TSAB negative). The effect of TSHR activation was then analyzed using human primary abdominal subcutaneous preadipocytes (n = 16). Cells were cultured in complete medium (CM) or adipogenic medium [ADM, containing thiazolidinedione (TZD), PPARγ agonist, which is able to induce BAT formation] with or without TSHR activation (gain-of-function mutant) for 3 weeks. Adipogenesis was evaluated using oil red O (ORO), counting adipogenic foci, qPCR measurement of terminal differentiation marker (LPL). BAT [PGC-1α, uncoupling protein 1 (UCP1), and ZIC1], pre-BAT (PRDM16), BRITE− (CITED1), or WAT (LEPTIN) markers were analyzed by semiquantitative PCR or qPCR. In ex vivo analysis, there were no differences in the expression of UCP1, PGC-1α, and ZIC1. BRITE marker CITED1 levels were highest in GD followed by TMNG and control (p for trend = 0.009). This was associated with higher WAT marker LEPTIN level in GD than the other two groups (p < 0.001). In primary cell culture, TSHR activation substantially enhanced adipogenesis with 1.4 ± 0.07 (ORO), 8.6 ± 1.8 (foci), and 5.5 ± 1.6 (LPL) fold increases compared with controls. Surprisingly, TSHR activation in CM also significantly increased pre-BAT marker PRDM16; furthermore, TZD-ADM induced adipogenesis showed substantially increased BAT markers, PGC-1α and UCP1. Our study revealed that TSHR activation plays an important role in the adipogenesis process and BRITE/pre-BAT formation, which leads to WAT or BAT phenotype. It may contribute to weight loss as heat during hyperthyroidism and later transforms into WAT posttreatment of GD when patients gain excess weight.
... Previous studies have demonstrated that DHEA exerts anti-proliferative effects in animal tumor models and in malignant cell lines (10)(11)(12) through its inhibitory effects on G6PD activity, which is essential for cell growth (6,11). A previous study demonstrated that DHEA inhibits 3T3-L1 cell proliferation, which was associated with G1 phase cell cycle arrest (13). Zapata et al (14) demonstrated that DHEA inhibits mesodermal cell proliferation. ...
... It has been previously reported that ethanol treatment results in a slight decrease in cell viability. In the previous study, cell viability was decreased by 8% at 1% ethanol, which was highest final concentration used (13). The present study demonstrated that the cell viability gradually improved throughout the experimental period in the control group (0.1% DMSO), which indicated that normal cell growth was maintained. ...
Dehydroepiandrosterone (DHEA) is widely used as a nutritional supplement and exhibits putative anti‑aging properties. However, the molecular basis of the actions of DHEA, particularly on the biological characteristics of target cells, remain unclear. The aim of the current study was to investigate the effects of DHEA on cell viability, cell proliferation, cell cycle and mitochondrial function in primary rat Leydig cells. Adult Leydig cells were purified by Percoll gradient centrifugation, and cell proliferation was detected using a Click-iT® EdU Assay kit and cell cycle assessment performed using flow cytometry. Mitochondrial membrane potential was detected using JC-1 staining assay. The results of the current study demonstrate that DHEA decreased cell proliferation in a dose‑dependent manner, whereas it improved cell viability in a time‑dependent and dose‑dependent manner. Flow cytometry analysis demonstrated that DHEA treatment increased the S phase cell population and decreased the G2/M cell population. Cyclin A and CDK2 mRNA levels were decreased in primary rat Leydig cells following DHEA treatment. DHEA treatment decreased the transmembrane electrical gradient in primary Leydig cells, whereas treatment significantly increased succinate dehydrogenase activity. These results indicated that DHEA inhibits primary rat Leydig cell proliferation by decreasing cyclin mRNA level, whereas it improves cells viability by modulating the permeability of the mitochondrial membrane and succinate dehydrogenase activity. These findings may demonstrate an important molecular mechanism by which DHEA activity is mediated.
... In agreement with two other studies on the effects of the steroid hormone dehydroepiandrosterone (DHEA) on human pre-adipocytes, the proliferation of PAZ6 cells, tested in parallel with 3T3-L1 and human primary pre-adipocytes, was significantly inhibited (Rice et al., 2010). The effect was observed in both cell lines under a 24 h exposure of 100 nM to 100 μM DHEA. ...
... The effect was observed in both cell lines under a 24 h exposure of 100 nM to 100 μM DHEA. Intraadipocyte DHEA concentration is an order of magnitude higher than the circulating levels which are within the nanomolar range, so the concentrations used in those test were within physiological levels (Rice et al., 2010). The transcriptional activity of the wild-type or a variant UCP2 promoter was analyzed in PAZ6 cells. ...
The role of brown adipose tissue (BAT) in human metabolism and its potential as an anti-obesity target organ have recently received much renewed attention. Following radiological detection of substantial amounts of BAT in adults by several independent research groups, an increasing number of studies are now dedicated to uncover BAT’s genetic, developmental, and environmental determinants. In contrast to murine BAT, human BAT is not present as a single major fat depot in a well-defined location. The distribution of BAT in several areas in the body significantly limits its availability to research. A human brown adipocyte cell line is therefore critical in broadening the options available to researchers in the field. The human BAT-cell line PAZ6 was created to address such a need and has been well characterized by several research groups around the world. In the present review, we discuss their findings and propose potential applications of the PAZ6 cells in addressing the relevant questions in the BAT field, namely for future use in therapeutic applications.
... При кучета със затлъстяване вероятните механизми са повишена оксидация на пероксидазната активност, повишена продукция на инсулин и инсулинова чувствителност, понижаване на TNF (62). В клетъчни култури на гризачи намалява преадипоцитната пролиферация, акумулацията на ТГ в мастни и чернодробни клетки, намалява експресията на PPARγ (63,64,65). Предполага се, че тези ефекти са медиирани от андрогенния рецептор (66). ...
Dehydroepiandrosterone (DHEA) and its sulfated forma (DHEA-S) are the endogenous steroids with the highest concentrations, fulfilling the role of androgen precursors. This review discusses the current understanding of the physiological role of DHEA-S in different stages of life, as well as the biological effects of its metabolites. Accent is put on the role of DHEA-S in the context of cardiovascular disease as a factor influencing the pathogenesis of ischemic heart disease and the cardiovascular risk factors. The studies reviewed outline DHEA-S as one of the possible factors influencing atherogenesis, turning it into a likely subject of future research.
... [15][16][17][18][19] Conversely, it appears that the adrenal prohormones dehydroepiandrosterone (DHEA) and dehydroepiandrosterone sulfate (DHEAS) have a beneficial effect by inhibiting the proliferation and differentiation of subcutaneous adipocyte and adipogenesis in omental adipocyte and enhancing adipocyte glucose uptake. [20][21][22] Furthermore, DHEA seems to exert antiglucocorticoid action on preadipocyte proliferation and differentiation, and DHEAS stimulates lipolysis. 23,24 Different effects of adrenal prohormones on the development of harmful subphenotypes in PCOS, when compared with the effects of testosterone and free testosterone index, have been reported. ...
Objective To examine the possible effects of adrenal prohormones in the prediction of clinical and metabolic abnormalities in women with polycystic ovary syndrome (PCOS).
Methods The present study enrolled 299 normal cycling non-PCOS, 156 normoandrogenemic, and 474 hyperandrogenemic women with PCOS. Baseline characteristics were compared using a chi-squared test or analysis of variance (ANOVA) as appropriate. The roles of adrenal prohormones and their ratios with total testosterone in predicting co-occurring morbidities in women PCOS were evaluated using univariate and multivariate logistic regression analyses.
Results Adrenal hyperandrogenism per dehydroepiandrosterone sulfate (DHEAS) levels were found in 32% of women with PCOS. In non-PCOS women, dehydroepiandrosterone (DHEA) and its sulfate had no predictive role concerning clinical, anthropometric, and metabolic parameters. In PCOS women, mainly in the hyperandrogenemic group, DHEA showed to be a significant predictor against most anthropometric-metabolic index abnormalities (odds ratio [OR] = 0.36–0.97; p < 0.05), and an increase in triglycerides (TG) levels (OR = 0.76; p = 0.006). Dehydroepiandrosterone sulfate presented a few predictive effects regarding PCOS-associated disorders. In controls, DHEAS predicted against the increase in estimated average glucose (OR= 0.38; p = 0.036). In the normoandrogenic group, it predicted against elevation in the waist/hip ratio (WHR) (OR= 0.59; p = 0.042), and in hyperandrogenemic PCOS women, it predicted against abnormality in the conicity index (CI) (OR = 0.31; p = 0.028).
Conclusion Dehydroepiandrosterone was shown to be a better predictor of abnormal anthropometric and biochemical parameters in women with PCOS than DHEAS. Thus, regarding adrenal prohormones, DHEA measurement, instead of DHEAS, should be preferred in PCOS management. The effects of androgen prohormones on the prediction of PCOS abnormalities are weak.
... Namely, proliferation of preadipocytes is upregulated by estrogens with greater effects in preadipocytes isolated from SAT vs. VAT and females vs. males [79]. In turn, androgens hamper adipogenesis in in vitro and in vivo trials and the effects are greater in preadipocytes from VAT vs. SAT [79,[86][87][88][89][90]. ...
The gonadal steroids, including androgens, estrogens and progestogens, are involved in the control of body fat distribution in humans. Nevertheless, not only the size and localization of the fat depots depend on the sex steroids levels, but they can also highly affect the functioning of adipose tissue. Namely, the gonadocorticoids can directly influence insulin signaling, lipid metabolism, fatty acid uptake and adipokine production. They may also alter energy balance and glucose homeostasis in adipocytes in an indirect way, e.g., by changing the expression level of aquaglyceroporins. This work presents the recent advances in understanding the molecular mechanism of how the gonadal steroids influence the functioning of adipose tissue leading to a set of detrimental metabolic consequences. Special attention is given here to highlighting the sexual dimorphism of adipocyte functioning in terms of health and disease. Particularly, we discuss the molecular background of metabolic disturbances occurring in consequence of hormonal imbalance which is characteristic of some common endocrinopathies such as the polycystic ovary syndrome. From this perspective, we highlight the potential drug targets and the active substances which can be used in personalized sex-specific management of metabolic diseases, in accord with the patient’s hormonal status.
... Furthermore, DHEA inhibits proliferation and differentiation of human subcutaneous adipocyte cells and enhances glucose uptake (Perrini et al., 2004;Karbowska and Kochan, 2013). DHEA upregulates adipocyte resistin production (Kochan and Karbowska, 2004) and inhibits adipogenesis in omental adipocyte (Rice et al., 2010), protecting against increased visceral fat accumulation (Hansen et al., 1997). E2 receptors are expressed in adipocyte cells and, in vitro, upregulate resistin mRNA expression through extracellular signal-regulated kinases (ERK) and cytosine-cytosine-adenine-adenosine-thymidine (CCAAT) enhancer-binding protein-a (C/EBS) (Chen et al., 2006). ...
BACKGROUND
Metabolic and endocrine alterations in women with polycystic ovary syndrome (PCOS) affect adipose tissue mass and distribution. PCOS is characterised by hyperandrogenism, obesity and adipocyte dysfunction. Hyperandrogenism in PCOS drives dysfunctional adipocyte secretion of potentially harmful adipocytokines. Glucocorticoids and sex-steroids modulate adipocyte development and function. For their part, adipocyte products interact with adrenal and ovarian steroidogenic cells. Currently, the relationship between adipocyte and steroidogenic cells is not clear, and for these reasons, it is important to elucidate the interrelationship between these cells in women with and without PCOS.
OBJECTIVE AND RATIONALE
This comprehensive review aims to assess current knowledge regarding the interrelationship between adipocytes and adrenal and ovarian steroidogenic cells in animal models and humans with or without PCOS.
SEARCH METHODS
We searched for articles published in English and Portuguese in PubMed. Keywords were as follows: polycystic ovary syndrome, steroidogenesis, adrenal glands, theca cells, granulosa cells, adipocytes, adipocytokines, obesity, enzyme activation, and cytochrome P450 enzymes. We expanded the search into the references from the retrieved articles.
OUTCOMES
Glucocorticoids and sex-steroids modulate adipocyte differentiation and function. Dysfunctional adipocyte products play important roles in the metabolic and endocrine pathways in animals and women with PCOS. Most adipokines participate in the regulation of the hypothalamic–pituitary–adrenal and ovarian axes. In animal models of PCOS, hyperinsulinemia and poor fertility are common; various adipokines modulate ovarian steroidogenesis, depending on the species. Women with PCOS secrete unbalanced levels of adipocyte products, characterised by higher levels of leptin and lower levels of adiponectin. Leptin expression positively correlates with body mass index, waist/hip ratio and levels of total cholesterol, triglyceride, luteinising hormone, oestradiol and androgens. Leptin inhibits the production of oestradiol and, in granulosa cells, may modulate 17-hydroxylase and aromatase enzyme activities. Adiponectin levels negatively correlate with fat mass, body mass index, waist–hip ratio, glucose, insulin and triglycerides, and decrease androgen production by altering expression of luteinising hormone receptor, steroidogenic acute regulatory protein, cholesterol-side-chain cleavage enzyme and 17-hydroxylase. Resistin expression positively correlates with body mass index and testosterone, and promotes the expression of 17-hydroxylase enzyme in theca cells. The potential benefits of adipokines in the treatment of women with PCOS require more investigation.
WIDER IMPLICATIONS
The current data regarding the relationship between adipocyte products and steroidogenic cells are conflicting in animals and humans. Polycystic ovary syndrome is an excellent model to investigate the interrelationship among adipocyte and steroidogenic cells. Women with PCOS manifest some pathological conditions associated with hyperandrogenism and adipocyte products. In animals, cross-talk between cells may vary according to species, and the current review suggests opportunities to test new medications to prevent or even reverse several harmful sequelae of PCOS in humans. Further studies are required to investigate the possible therapeutic application of adipokines in women with obese and non-obese PCOS. Meanwhile, when appropriate, metformin use alone, or associated with flutamide, may be considered for therapeutic purposes.
... Furthermore, the adipocyte size in both the DHEA-treated and control were similar in the present study. This finding is similar to other studies in which DHEA showed antiproliferative and anti-adipogenic effects in both 3T3-L1 preadipocyte and human adipose tissue [19,20]. Therefore, even Fig. 6. ...
Objective
Hyperandrogenism is the hallmark of polycystic ovary syndrome (PCOS). The use of dehydroepiandrosterone (DHEA)-treated rats is thought to be a suitable animal model to study PCOS. In the present study, we assessed the severity of reproductive and metabolic abnormalities in DHEA-treated rats.
Material and methods
Immature female Sprague–Dawley rats were divided into control and DHEA-treated groups. Reproductive parameters including estrus cycle and sex hormones were measured after sexual maturity. Adiposity, insulin sensitivity, and plasma lipid profiles were analyzed to assess metabolic profiles. After sacrifice, the insulin signaling pathway and lipogenic genes were analyzed by immunoblotting and polymerase chain reaction, respectively.
Results
An abnormal estrus cycle was observed in the DHEA-treated rats. DHEA treatment also increased plasma testosterone levels and caused multiple cystic follicle formation, which is compatible with the definition of PCOS. There were no significant changes in fasting glucose, fasting insulin, plasma lipid profiles, and blood pressure levels. The adiposity of the DHEA-treated rats was also lower than in the control rats. Moreover, glucose tolerance and insulin sensitivity were only mildly impaired in the DHEA-treated rats after oral glucose tolerance and insulin tolerance tests, even though insulin signaling in skeletal muscles was decreased in the DHEA-treated group.
Conclusion
DHEA-treated rats had reproductive abnormalities which mimicked symptoms of human PCOS. In metabolic parameters, DHEA treatment did not show insulin resistance in the female rats, suggesting that the use of DHEA-treated rats is not a good animal model for the study of metabolic abnormalities in PCOS.
... 43,[45][46][47] In fact, androgens induce adipocyte hypertrophy and inflammation and decrease the adipocyte sensitivity to insulin sensitivity. 48 By contrast, DHEA has been shown to inhibit proliferation of adipocytes to enhance glucose uptake 49,50 and to have a cardioprotective role in a number of studies. 51 DHEAS stimulates lipolysis. ...
Background:
To evaluate anthropometric-metabolic biomarkers as predictors of metabolic syndrome (MS) in women with polycystic ovary syndrome (PCOS) with and without obesity.
Methods:
This was an observational cross-sectional study. Patients were classified as nonobese-PCOS (body mass index, BMI <30 kg/m2, n = 385), and obese-PCOS (BMI ≥30 kg/m2, n = 261). The anthropometric parameters waist circumference, waist/hip ratio, lean body mass, fat body mass, visceral adiposity index (VAI), lipid accumulating product, and biomarkers of glucose and lipid metabolisms were compared between groups. Binominal logistic regression analyses were performed to identify predictors of MS.
Results:
Obesity was diagnosed in 40% of all PCOS women (P < 0.001). Blood pressure and anthropometric abnormalities were significantly more frequent in obese-PCOS women (P < 0.001, for all comparisons). Glucose metabolism markers were higher in obese-PCOS compared with nonobese-PCOS (P < 0.001, for all comparisons). High-density lipoprotein cholesterol was lower in obese group than in nonobese group (1.26 mM vs. 1.08 mM, P < 0.001). MS was found in 23 of 385 (6%) nonobese-PCOS and in 116 of 261 (44.4%) obese-PCOS (P < 0.001). VAI was the best predictor of MS in both nonobese-PCOS (OR = 4.1, 95% CI 1.5-11.1) and obese-PCOS (OR = 12.9, 95% CI 5.7-29.0).
Conclusions:
MS is more prevalent in PCOS women with obesity. VAI was the strongest predictor of MS in both obese and nonobese PCOS women, and can be applied in clinical practice for early detection of risk for MS and precocious intervention in women with PCOS, particularly in obese women.
... Adipogenesis was assessed by microscopic examination to detect the characteristic morphological changes (cell rounding, accumulation of lipid droplets), acquisition of lipid-filled droplets (oil red O staining, ORO) and transcript measurement of the adipogenic terminal differentiation marker lipoprotein lipase (LPL) by QPCR as described previously [35]. In addition, foci of differentiation (groups of cells with lipid droplets) were counted in ten different fields for each experimental condition [36]. ...
Hyaluronan (HA), an extra-cellular matrix glycosaminoglycan, may play a role in mesenchymal stem cell differentiation to fat but results using murine models and cell lines are conflicting. Our previous data, illustrating decreased HA production during human adipogenesis, suggested an inhibitory role. We have investigated the role of HA in adipogenesis and fat accumulation using human primary subcutaneous preadipocyte/fibroblasts (PFs, n = 12) and subjects of varying body mass index (BMI). The impact of HA on peroxisome proliferator-activated receptor gamma (PPARγ) expression was analysed following siRNA knockdown or HA synthase (HAS)1 and HAS2 overexpression. PFs were cultured in complete or adipogenic medium (ADM) with/without 4-methylumbelliferone (4-MU = HA synthesis inhibitor). Adipogenesis was evaluated using oil red O (ORO), counting adipogenic foci, and measurement of a terminal differentiation marker. Modulating HA production by HAS2 knockdown or overexpression increased (16%, p < 0.04) or decreased (30%, p = 0.01) PPARγ transcripts respectively. The inhibition of HA by 4-MU significantly enhanced ADM-induced adipogenesis with 1.52 ± 0.18- (ORO), 4.09 ± 0.63- (foci) and 2.6 ± 0.21-(marker)-fold increases compared with the controls, also increased PPARγ protein expression (40%, (p < 0.04)). In human subjects, circulating HA correlated negatively with BMI and triglycerides (r = −0.396 (p = 0.002), r = −0.269 (p = 0.038), respectively), confirming an inhibitory role of HA in human adipogenesis. Thus, enhancing HA action may provide a therapeutic target in obesity.
... In vitro, estrogens stimulate proliferation of human preadipocytes, 48,49 whereas androgens inhibit differentiation without affecting proliferation. 50,51 Apart from regulating fuel homeostasis, adipose tissue releases a large number of secretory products such as adipokines, chemokines, and cytokines. Some of these factors are known to display sex differences in their secretion and regulation and also contribute to fuel homeostasis. ...
Impact statement:
Traditional sex-related biases in research are now obsolete, and it is important to identify the sex of humans, animals, and even cells in research protocols, due to the role of sex as a fundamental facet of biology, predisposition to disease, and response to therapy. Genetic sex, epigenetics and hormonal regulations, generate sex-dimorphisms. Recent investigations acknowledge sex differences in metabolic and immune health as well as chronic diseases. Prohibitin, an evolutionarily conserved molecule, has pleotropic functions in mitochondrial housekeeping, plasma membrane signaling, and nuclear genetic transcription. Studies in adipocytes, macrophages, and transgenic mice indicate that prohibitin interacts with sex steroids and plays a role in mediating sex differences in adipose tissues and immune cell types. Prohibitin may, depending on context, modulate predisposition to chronic metabolic diseases and malignancy and, because of these attributes, could be a target for sex-based therapies of metabolic and immune-related diseases as well as cancer.
... It is a precursor of sex hor- mones and enters the blood circulation in the form of its sulfate ester (DHEA-S) [10]. It can be converted to estrogen, androgen, progestogen, corticosterone, and other hormones through the action of different enzymes [11]. Frolova et al. [12] flux by inhibiting the pentose phosphate pathway. ...
... DHEA (5 μM) was reported to protect mouse hippocampal cell line HT-22 from the toxicity induced by glutamate (5 mM) by decreasing nuclear GR levels (Cardounel, Regelson, & Kalimi, 1999). DHEA, but not Adione, Adiol, or T, inhibited proliferation of human PAZ6 preadipocytes, a cell line derived from human brown adipose tissue (BAT), and adipogenesis in omental but not subcutaneous preadipocytes (Rice et al., 2010). More recent studies using telomerase-immortalized Chub-S7 human subcutaneous adipocytes showed that OATP-D, an influx transporter of DHEA-S, and STS were expressed in Chub-S7 in which DHEA was converted to androstenediol, but not to DHEA-S (McNelis et al., 2013). ...
Dehydroepiandrosterone (3β-hydroxy-5-androsten-17-one, DHEA) and its sulfated metabolite DHEA-S are the most abundant steroids in circulation and decline with age. Rodent studies have shown that DHEA has a wide variety of effects on liver, kidney, adipose, reproductive tissues, and central nervous system/neuronal function. The mechanisms by which DHEA and DHEA-S impart their physiological effects may be direct actions on plasma membrane receptors, including a DHEA-specific, G-protein-coupled receptor in endothelial cells; various neuroreceptors, e.g., aminobutyric-acid-type A, N-methyl-D-aspartate (NMDA), and sigma-1 (S1R) receptors; by binding steroid receptors: androgen and estrogen receptors (ARs, ERα, or ERβ); or by their metabolism to more potent sex steroid hormones, e.g., testosterone, dihydrotestosterone, and estradiol, which bind with higher affinity to ARs and ERs. DHEA inhibits voltage-gated T-type calcium channels. DHEA activates peroxisome proliferator-activated receptor (PPARα) and CAR by a mechanism apparently involving PP2A, a protein phosphatase dephosphorylating PPARα and CAR to activate their transcriptional activity. We review our recent study showing DHEA activated GPER1 (G-protein-coupled estrogen receptor 1) in HepG2 cells to stimulate miR-21 transcription. This chapter reviews some of the physiological, biochemical, and molecular mechanisms of DHEA and DHEA-S activity.
... A number of epidemiologic studies have shown correlations between circulating DHEA-S and obesity and insulin resistance and cardiovascular disease [51]. Both in vitro and in vivo studies have demonstrated antiadipogenic effects of DHEA on animal adipocytes [52]. DHEA effects favorable changes in adipocyte insulin sensitivity and adipokine profile [53,54]. ...
Adipose tissue and the adrenal glands both play fundamental roles in the regulation of normal physiology and in the development of metabolic pathology. There has been an increasing awareness of the complex interactions between adipose tissue and the adrenal glands. Adipose tissue-derived efferent signals are implicated in a variety of alterations in adrenal function. Adipocyte-derived secretory products such as adiponectin and leptin have direct effects on adrenfal steroidogenesis, glucocorticoid metabolism, adrenal medullary catecholamine output and hypothalamic-pituitary-adrenal (HPA) axis function. Moreover, glucocorticoids and mineralocorticoids likely play a crucial role in the development of obesity and insulin resistance through elaborate mechanisms. Augmenting the effects of adrenal steroid hormones on adipose tissue is the enhanced activity of the mineralocorticoid receptor in adipocytes. Elevated adrenal steroid levels have been associated with weight gain, changes in body fat distribution and alterations in circulating levels of several adipose tissue hormones, or “adipokines." In this chapter, we summarize the current literature regarding the two-way communication between the adrenal glands and adipose tissue; emphasizing the possible mechanisms of interactions between these two endocrine organs and its relevance to the pathogenesis of obesity and associated comorbidities, metabolic syndrome, and in primary adrenal disorders.
... By contrast, UCP1 mRNA levels are higher in PAZ6 cells differentiated in the presence of DHEA. The inhibitory effect on PAZ6 pre-adipocyte cell cycle progression and the promoting effect on PAZ6 adipocyte gene expression may represent a pro-adipogenic mechanism (Rice et al., 2010). In PAZ6 adipocytes, retinoic acid increases UCP1 gene expression in a PGC1α-dependent way, while the PPARα-specific agonist, WY14643, failed to regulate UCP1 gene expression without RA (Oberkofler et al., 2002). ...
Obesity, which underlies various metabolic and cardiovascular diseases, is a growing public health challenge for which established therapies are inadequate. Given the current obesity epidemic, there is a pressing need for more novel therapeutic strategies that will help adult individuals to manage their weight. One promising therapeutic intervention for reducing obesity is to enhance energy expenditure. Investigations into human brown fat and the recently discovered beige/brite fat have galvanized intense research efforts during the past decade because of their pivotal roles in energy dissipation. In this review, we summarize the evolution of human brown adipose tissue (hBAT) research and discuss new in vivo methodologies for evaluating energy expenditure in patients. We highlight the differences between human and mouse BAT by integrating and comparing their cellular morphology, function, and gene expression profiles. Although great advances in hBAT biology have been achieved in the past decade, more cellular models are needed to acquire a better understanding of adipose-specific processes and molecular mechanisms. Thus, this review also describes the development of a human brown fat cell line, which could provide promising mechanistic insights into hBAT function, signal transduction, and development. Finally, we focus on the therapeutic potential and current limitations of hBAT as an anti-glycemic, anti-lipidemic, and weight loss-inducing ‘metabolic panacea’.
... A series of studies suggest that supplementation with DHEA in animal models and humans could have beneficial effects on multiple physiologic functions [9][10][11][12][13], resulting in widespread self-administration of DHEA in the USA as an anti-aging drugs, where it is considered to be a food supplement and is available without prescription. Previous studies mainly focused on the metabolism of exogenous DHEA in testis [14], Leydig cells [15], ovariectomy [16] or natural menopause [17]. ...
Dehydroepiandrosterone (DHEA) is important for human health, especially for women. All estrogens and practically half of androgens are synthesized from DHEA in peripheral tissues. However, the mechanism and exact target tissues of DHEA biotransformation in the female are not fully clear. The present study showed that maximal content of androstenedione (AD) and testosterone (T) were observed at 3h after DHEA administration in female rats, which was 264% and 8000% above the control, respectively. Estradiol (E2) content significantly increased at 6h after DHEA administration, which was 113% higher than that in control group. Gavage with DHEA could significantly reduce 3β-hydroxysteroid dehydrogenase (3β-HSD) mRNA level at 3-12h and 17β-hydroxysteroid dehydrogenase (17β-HSD) mRNA level at 12h in ovary, while increasing aromatase mRNA levels at 6, 24, and 48 h. It is interesting that administration of DHEA caused a significant increase of 17β-HSD, 3β-HSD and aromatase mRNA levels in adrenal. The AD and T contents also markedly increased by 537% and 2737% after DHEA administration in ovariectomised rats, in company with a significant increase in 17β-HSD and 3β-HSD mRNA levels and decreased aromatase mRNA level in adrenal. However, DHEA administration did not restore the decreased E2, estrone (E1), and progesterone (P) caused by the removal of the ovaries in females. These results clearly illustrated that exogenous DHEA is preferentially converted into androgens in adrenal, while its conversion to estrogens mainly happens in the ovary through steroidogenic enzyme in female rats.
... In in-vitro trials it has been shown that DHEA can inhibit adipogenesis in human subcutaneous tissue. This effect has not been confirmed for subcutaneous adipose tissue [32]. ...
Epidemiological studies have shown that low levels of dehydroepiandrosterone might increase the risk of developing metabolic syndrome. The aim of this study was to evaluate whether dehydroepiandrosterone supplementation in schizophrenic patients treated with olanzapine would influence the anthropometric and biochemical parameters of metabolic syndrome.
Male schizophrenic patients (no=55) participated in a twelve-week, randomized, double blind, placebo controlled study. They received 100 mg dehydroepiandrosterone (DHEA) or placebo as an augmentation of olanzapine treatment (an average dosage 15 mg/day). Main outcomes of the study were changes in lipid profile, fasting glucose levels, body mass index and waist circumference values.
Forty five patients completed the study. There were no major changes in the overall cholesterol value, HDL cholesterol, LDL cholesterol or triglycerides in either group. The results of the repeated measures analysis of the system: fasting glucose level 2x, (at the beginning and end of the study), 2x (the study group and the control group), showed a significant interaction (F =5.7, df= 1.000 p= 0.021). The blood glucose level was decreased in the DHEA group. Furthermore, increases in waist circumference (delta= -1.11, t=-2.87; df=20; p=0.01) and BMI value (delta= -0.48, t=-2.38; df=19; p=0.028) were observed in the placebo group.
Dehydroepiandrosterone supplementation results in stabilization of BMI, waist circumference and fasting glycaemia values in schizophrenic patients treated with olanzapine. To confirm the insulin-like effect of dehydroepiandrosterone, long-term research concentrating on the evaluation of glucose metabolism has to be performed.
... We [167] and others [165,166] found that these effects were partially reversed by anti-androgens flutamide or bicalutamide. One study reported that DHEA inhibits adipogenesis specifically in omental fat [168] which could be mediated by androgenic metabolites of this steroid [169]. Studies on androgens and lipolysis are not unanimous. ...
... A number of epidemiologic studies have shown correlations between circulating DHEA-S and obesity and insulin resistance and cardiovascular disease [51]. Both in vitro and in vivo studies have demonstrated antiadipogenic effects of DHEA on animal adipocytes [52]. DHEA effects favorable changes in adipocyte insulin sensitivity and adipokine profile [53,54]. ...
Hormones produced by the adrenal glands and adipose tissues have important roles in normal physiology and are altered in many disease states. Obesity is associated with changes in adrenal function, including increase in adrenal medullary catecholamine output, alterations of the hypothalamic-pituitary-adrenal (HPA) axis, elevations in circulating aldosterone together with changes in adipose tissue glucocorticoid metabolism, and enhanced adipocyte mineralocorticoid receptor activity. It is unknown whether these changes in adrenal endocrine function are in part responsible for the pathogenesis of obesity and related comorbidities or represent an adaptive response. In turn, adipose tissue hormones or "adipokines" have direct effects on the adrenal glands and interact with adrenal hormones at several levels. Here we review the emerging evidence supporting the existence of "cross talk" between the adrenal gland and adipose tissue, focusing on the relevance and roles of their respective hormones in health and disease states including obesity, metabolic syndrome, and primary disorders of the adrenals.
... Again, inguinal preadipocyte differentiation was unaffected or increased, whereas omental preadipocytes showed significantly reduced adipogenesis. 42 Reduced adipogenesis might be explained by the induction of apoptosis. Hallenborg et al. 43 showed that p53 inhibits adipogenesis and maintains adipose tissue function. ...
Objective:
The endocannabinoid system is a major component in the control of energy metabolism. Cannabinoid 1 (CB1)-receptor blockade induces weight loss and reduces the risk to develop the metabolic syndrome with its associated cardiovascular complications. These effects are mediated by central and peripheral pathways. Interestingly, weight loss is mainly achieved by a reduction of visceral fat mass. We analyzed fat depot-specific differences on adipocyte differentiation, inflammation and oxidative metabolism in CB1-receptor knockout cells.
Materials and methods:
We used newly generated epididymal/inguinal adipose cell lines from CB1-receptor knockout mice. Differences in differentiation were measured by fat-specific Oil Red O staining and quantitative analysis of key differentiation markers. Induction of apoptosis was evaluated by cell death detection and investigation of p53 phosphorylation. Inflammation markers were quantified by real-time PCR. For analyzing the process of transdifferentiation we measured oxygen consumption and mitochondrial biogenesis.
Results:
Differentiation was reduced in visceral adipocytes from CB1-receptor knockout mice as compared with wild-type controls. Moreover, we found an induction of apoptosis in these cells. In contrast, subcutaneous adipocytes from CB1-receptor knockout mice showed an accelerated differentiation and a reduced rate of apoptosis. Inflammation was increased in visceral fat cells, as analyzed by the expression pattern of interleukin-6, monocyte chemoattractant protein 1 (MCP-1), tumor necrosis factor-α, whereas in subcutaneous adipocytes these markers were decreased. Furthermore, subcutaneous CB1-receptor knockout cells were more sensitive toward a conversion into a brown fat phenotype. Uncoupling protein-1 as well as PGC-1α expression was significantly elevated. This was accompanied by an increase in mitochondrial biogenesis and oxygen consumption.
Conclusion:
In conclusion, we found depot-specific effects on differentiation, apoptosis, inflammation and oxidative metabolism in CB1-receptor knockout cells. Thus, CB1-receptor-mediated pathways differentially target adipose tissue depots to a dual effect that minimizes cardiometabolic risk, on the one hand, by diminishing visceral fat, and that enhances thermogenesis in subcutaneous adipocytes, on the other.
... The intracellular mechanisms by which DHEA reduces body fat accumulation are not fully elucidated. DHEA has been shown to inhibit proliferation and differentiation of adipocytes [13], to increase energy expenditure and resting metabolic rate [14], and to exert anti-glucocorticoid action in adipose tissue by suppression of 11b-hydroxysteroid dehydrogenase type 1 (11b-HSD1) activity [15,16]. Tagliaferro et al. [8] have proposed that the effect of DHEA on adiposity may involve increased mobilization of triglycerides stored in adipose tissue. ...
... Interestingly, in vitro proliferation and differentiation of preadipocytes isolated from the same individuals were comparable between sexes, leading these authors to suggest that the local microenvironment rather than inherent cellular differences promotes adipogenesis in women [166]. In vitro, estrogens stimulate proliferation of human preadipocytes [167,168] , whereas androgens inhibit differentiation without affecting proliferation [158,169]. However, whether specific depots are differentially sensitive to sex steroid effects and potential sex-differences in response to these hormones are yet to be systemically investigated. ...
Women have more body fat than men, but in contrast to the deleterious metabolic consequences of the central obesity typical of men, the pear-shaped body fat distribution of many women is associated with lower cardiometabolic risk. To understand the mechanisms regulating adiposity and adipose tissue distribution in men and women, significant research attention has focused on comparing adipocyte morphological and metabolic properties, as well as the capacity of preadipocytes derived from different depots for proliferation and differentiation. Available evidence points to possible intrinsic, cell autonomous differences in preadipocytes and adipocytes, as well as modulatory roles for sex steroids, the microenvironment within each adipose tissue, and developmental factors. Gluteal-femoral adipose tissues of women may simply provide a safe lipid reservoir for excess energy, or they may directly regulate systemic metabolism via release of metabolic products or adipokines. We provide a brief overview of the relationship of fat distribution to metabolic health in men and women, and then focus on mechanisms underlying sex differences in adipose tissue biology.
... These cells transform into preadipocytes, which are difficult to distinguish from stem cells, proliferate, and then terminally differentiate into mature adipocytes (40). Because proliferative activity is considered to be eliminated in mature adipocytes (16), we noted a nonmature adipocyte fraction of adipose tissue, stromal vascular fraction (SVF), consisting of adipocyte progenitor cells, mature endothelial cells, and angiogenic progenitor cells (38), and immune cells including macrophages (47). Newborn adipocytes are provided from the SVF, and the efficacy of adipogenesis vastly influences adiposity and insulin sensitivity (54). ...
Several studies have suggested that both testosterone and dehydroepiandrosterone (DHEA) have weight-reducing and antidiabetic effects, especially in rodent studies; however, the precise mechanism of their action remains unclear. Here, we investigated the effect of DHEA on cell growth in adipose tissue. The appearance of senescence-associated β-galactosidase in stromal vascular fraction (SVF) isolated from Otsuka Long-Evans Tokushima fatty rats, an animal model of inherent obese type 2 diabetes, was prevented by DHEA administration. Next, the effects of DHEA and testosterone were compared in vivo and in vitro to evaluate whether these hormones influence cell growth in adipose tissue. Both DHEA and testosterone reduced body weight and epididymal fat weight equivalently when administered for 4 wk. To assess the effect of DHEA and testosterone on cell growth in adipose tissue, 5-bromo-2'-deoxyuridine (BrdU) uptake by SVF was measured. Quantification analysis of BrdU uptake by examining DNA isolated from each SVF revealed that treatment with DHEA and testosterone reduced cell replication. These results indicated that DHEA- and testosterone-induced decreased adiposity was associated with reduced SVF growth. Incubation with DHEA and testosterone equally decreased BrdU uptake by 3T3-L1 preadipocytes. Pretreatment with the androgen receptor (AR) inhibitor flutamide, but not the estrogen receptor inhibitor fulvestrant, abolished these effects. Knockdown of AR with siRNA also inhibited DHEA-induced decreases in BrdU uptake. These results suggest that DHEA-induced growth suppression of preadipocytes is mediated via AR. Therefore, both DHEA and testosterone similarly decrease adipocyte growth possibly via a common mechanism.
The rapid increase of obesity during the last few decades and its future prospects are alarming. Besides the generally discussed causes of obesity, the 'Developmental Origins of Health and Disease' (DOHaD) hypothesis has received more attention in recent years. This hypothesis postulates an adverse influence during early development that programs the unborn child for metabolic dysfunctions later in life. Childhood obesity – an as much increasing problem – can be predisposed by maternal overweight and diabetes. Both, obesity and hyperinsulinemia are major causes of female hyperandrogenemia. As predicted by the DOHaD hypothesis and shown in animal models, developmental androgen excess can lead to metabolic abnormalities in offspring. In this study, we investigated, if androgen-exposure adversely affects the adipogenic differentiation of preadipocytes and the endocrine function of adult adipocytes. The human SGBS preadipocyte model was used to affirm the de-novo biosynthesis of steroid hormones under normal adipogenesis conditions. Normal adipogenesis was paralleled by an increase of corticosteroids and androgens, whereas estrogen remained at a steady level. Treatment with androstenedione had no effect on SGBS proliferation and differentiation, but adult adipocytes exhibited a significant higher accumulation of triglycerides. Progesterone (up to 2-fold), testosterone (up to 38-fold) and cortisone (up to 1.4-fold) – but not cortisol – were elevated by androstenedione-administration in adult adipocytes. Estrogen was not altered. Data suggest that androgen does not negatively influence adipogenic differentiation but steroidogenic function of SGBS adipocytes.
Substantial evidence has linked dehydroepiandrosterone (DHEA) levels to the anti-obesity and anti-diabetic effects of exercise. While 5′-adenosine monophosphate-activated protein kinase (AMPK) is a negative regulator of adipocyte differentiation and lipid accumulation, activation of mammalian target of rapamycin complex 1 (mTORC1), which is inhibited by AMPK, is required for adipocyte differentiation and positively regulates lipid accumulation. DHEA treatment activates the AMPK pathway in C2C12 myotubes. Hence, DHEA addition to preadipocytes and adipocytes might activate AMPK and inhibit mTORC1, resulting in the inhibition of adipogenesis and lipid accumulation. Therefore, we investigated the effect of DHEA on the AMPK pathway, mTORC1 activity, adipocyte differentiation, and lipid accumulation in 3T3-L1 cells. DHEA suppressed lipid accumulation and adipogenic marker expression during differentiation. It also activated AMPK signaling in preadipocytes and adipocytes and suppressed mTORC1 activity during differentiation. These results suggest that the activation of the AMPK pathway and inhibition of mTORC1 activity may mediate the anti-obesity effect of DHEA, providing novel molecular-level insights into its physiological functions.
The mechanisms of mutual influence of fat tissue and the hypothalamo-pituitary-adrenal (HPA) axis include the regulation of the metabolism of adipocytes by adrenal cortex hormones, on the one part, and the effect of adipocytes and adipocytokines on secretion, metabolism and action of steroid hormones in target cells - on the other part.Glucocorticoids contribute to the differentiation of preadipocytes into mature adipocytes; brown fat tissue transforms into white under the effect of GC. Mineralocorticoids are also involved in the process of adipocyte differentiation, regulate adipokine expression, and induce oxidative stress in fat tissue. There is evidence that suggest that circulating dehydroepiandrosterone sulfate (DHEAS), obesity, insulin sensitivity are associated with the presence of cardiovascular diseases.Orexigenic neuropeptides and inflammatory mediators, which trigger the synthesis of corticotropin-releasing hormone (CRH) in the hypothalamic paraventricular nuclei, are considered as possible mechanisms of (HPA) axis activation in obesity. Expression of 1ip-hydroxysteroid dehydrogenase type 1 (11P-HSD1) in fat tissue and the formation of cortisol from cortisone at the tissue level can be considered as one of the factors involved in development of insulin resistance. The autocrine and paracrine regulatory effect of these hormones on adipocyte function is the consequence of aldosterone production and aromatization of androgens by fat tissue.
Background:
DHEA administration is potentially therapeutic because it has been shown to decrease fat mass and adipokines and improve eating and mood disturbances. However, its impact on these parameters has never been investigated in a young healthy population. This study therefore sought to determine whether short-term DHEA administration would alter food intake, segmental body composition, adipokine secretion and mood in young healthy male and female volunteers with regular sport practice.
Methods:
Following a double-blind and randomized protocol, 20 young healthy recreational athletes (10 men and 10 women) received treatment with either oral placebo or DHEA (100 mg/day for 4 weeks). Body weight, segmental body composition and adipokines (i.e., leptin, adiponectin and resistin) were determined before and at the end of each treatment. In parallel, spontaneous food intake was assessed at the end of each treatment, and mood was assessed before and at the end of treatment with the positive and negative affect schedule (PANAS).
Results:
Body weight and segmental body composition showed no significant change in the men or women. Similarly, no change in adipokine secretion was found after DHEA administration. Total food intake was not affected by DHEA in any subject, despite an increase in fat intake by male subjects under DHEA (p<0.05). Positive and negative affect were not altered.
Conclusions:
In conclusion, in contrast to pathological populations, a young healthy population of men and women was not significantly affected by short-term DHEA administration with regard to total food intake, segmental body composition, adipokines or mood.
Dehydroepiandrosterone (DHEA) possesses fat-reducing effect, while little information is available on whether DHEA regulates cell proliferation and mitochondrial function, which would, in turn, affect lipid droplet accumulation in broiler. In this study, the lipid droplet accumulation, cell proliferation, cell cycle and mitochondrial membrane potential were analysis in primary chicken hepatocytes treated with DHEA. The results showed that total area and counts of lipid droplet were significantly decreased in hepatocytes after DHEA treated. DHEA treatment significantly increased the cell viability, while the cell proliferation was significantly inhibited in a dose dependent manner in primary chicken hepatocytes treated with DHEA. DHEA treatment significantly increased the cell population of S phase and decreased the population of G2/M in primary chicken hepatocytes. Meanwhile, the cyclin A and cyclin-dependent kinases 2 (CDK2) mRNA abundance were significantly decreased in hepatocytes after DHEA treated. No significant differences were observed on the number of mitochondria, while the mitochondrial membrane permeability and succinate dehydrogenase (SDH) activity were significantly increased in hepatocytes treated with DHEA. In conclusion, our results demonstrated that DHEA reduced lipid droplet accumulation by inhibiting cell proliferation and enhancing mitochondrial function in primary chicken hepatocytes.
Dehydroepiandrosterone (DHEA) is widely used as a nutritional supplement due to its putative anti-aging properties. However, the effect of DHEA in Leydig cells, a major target cell of DHEA biotransformation in male, are not clear. The present study aimed to investigate the preventative effect of DHEA on oxidative damage and apoptosis after H2O2 treatment in Leydig cells. The results showed that DHEA treatment attenuated the reduction of cell viability induced by H2O2. No differences were observed on the superoxide anion (O2-) content, while DHEA treatment decreased reactive oxygen species (ROS) and hydroxyl radical (•OH) content in H2O2-treated Leydig cells. Pre-treatment with DHEA increased peroxidase (POD) activity and decreased glutathione peroxidase (GSH-Px) activity in H2O2-treated Leydig cell. DHEA treatment attenuated DNA damage as indicated by the decreasing of tail moment, comet length and olive tail moment. Total apoptosis ratio and early apoptosis ratio were significantly decreased in H2O2-treated Leydig cell that were pre-treatment with DHEA. DHEA treatment decreased Bax, capase-9 and capase-3 mRNA levels in H2O2-treated Leydig cells. Our results demonstrated that pre-treatment with DHEA prevented the Leydig cells oxidative damage caused by H2O2 through increasing POD activity, which resulted in inhibition of •OH generation. Meanwhile, pre-treatment with DHEA inhibited H2O2-induced Leydig cells early apoptosis which mainly by reducing the pro-apoptotic protein Bax and caspases-9, caspases-3 mRNA levels. This information is important to understand the molecular mechanism of anti-ageing effect and potential application in treatment of oxidative stress induced related diseases of DHEA.
With the increasing knowledge that gender impacts normal physiology, much biomedical research has begun to focus on the differential effects of sex on tissue function. Sexual dimorphism in mammals is due to the combined effects of both genetic and hormonal factors. Hormonal factors are mutable particularly in females where the estrous cycle dominates the hormonal milieu. Given the severity of the obesity epidemic and the fact that there are differences in obesity rates in men and women, the role of sex in white adipose tissue function is being recognized as increasingly important. Although sex differences in white adipose tissue distribution are well established, the mechanisms affecting differential function of adipocytes within white adipose tissue in males and females remain largely understudied and poorly understood. One of the largest differences in the endocrine environment in males and females is the concentration of circulating androgens and estrogens. This review examines the effects of androgens and estrogens on lipolysis/lipogenesis, adipocyte differentiation, insulin sensitivity, and adipokine production in adipocytes from white adipose tissue with a specific emphasis on the sexual dimorphism of adipocyte function in white adipose tissue during both health and disease.
ABSTRACT
The Human Papilloma Virus is the major cause of cervical cancer. Viral infection initiates cervical intraepithelial neoplasia which progresses through several stages to cervical cancer. 3,3’-diindolylmethane prevents or inhibits viral oncogene expression. Our objective is to identify the most effect minimum dose of diindolylmethane that prevents the progression from cervical dysplasia to carcinoma in situ. We document cervical histology in K14-HPV16 mice receiving different doses of diindolylmethane. Estrogen metabolites are also reported. We hypothesize that diindolylmethane may enhance the efficacy of prophylactic vaccines creating a new therapeutic use for these vaccines in women after viral infection. Viral oncogene suppression is a requirement for subsequent vaccination. Five doses (0 to 2500ppm) of diindolylmethane were incorporated into each mouse diet. The reproductive tract was serially sectioned and urine was obtained for analysis of estrogen metabolites and urinary diindolylmethane. Results indicate that 62% of mice receiving 1,000ppm diindolylmethane, remained dysplasia free after 20 weeks compared to 16% of mice receiving no DIM and 18% receiving 500ppm. 1000ppm completely suppressed the development of cervical cancer. Urinary estrogen metabolite levels indicated that diindolylmethane shifted estrogen metabolism toward C-2 hydroxylation at 2000ppm. C-16 metabolism was not induced. Urinary DIM levels increased as DIM in food increased. Evidence of a normal cervical epithelium after continuous DIM administration suggests suppressed oncogene expression. Lack of viral oncogene E6 and E7 expression could permit the development of protective antibodies following vaccine administration. The vaccine generated antibodies could also protect against re-infection by repeated exposure to the virus.
Both diabetes mellitus (DM) and obesity are prevalent in adults. The relationship between DM and body adipose tissue (AT) distribution is complex and although it has been investigated extensively, the subject remains controversial. Although a causal association between DM and obesity and AT distribution cannot be established on the basis of existing data, it is possible to conclude from many studies that gene, serum sex steroids level, daily physical activity and food supply can be the risk of obesity and AT redistribution factor among type 2 DM patients (T2DM). Obesity and AT redistribution of T2DM patients can increase the risk of insulin resistant (IR), cardiovascular disease and many other disorders. Even though obesity and AT redistribution screening or prophylactic treatment in all patients with T2DM is not being recommended at present, such patient populations should be given general guidelines regarding exercise, food intake control, and even medicinal treatment. The extent of diagnostic and therapeutic interventions should be based on the individual's risk profile.
Dehydroepiandrosterone (DHEA), a major steroid hormone, decreases with age, and this reduction has been shown to be associated with physical health. In the present study, the effect of DHEA on cell growth and mitochondrial function was investigated using TM-3 cells, a Leydig cell line. The growth of TM-3 cells exposed to 100 μM DHEA for 24h was inhibited due to cell cycle arrest, primarily in the S and G2/M phases, and this effect was caused by decreased activity of glucose-6-phosphate dehydrogenase (G6PD) and reduced expression of cyclinA and cyclinB mRNA. A novel finding was that DHEA improved TM-3 cell viability in a markedly time-dependent manner. Although no differences were observed in the configuration or number of TM-3 cell mitochondria following DHEA treatment, mitochondrial membrane permeability and the activity of succinate dehydrogenase (SDH) increased subsequent to 24h treatment of cells with 100 μM DHEA. Overall, the data demonstrate that DHEA inhibited TM-3 cell growth by decreasing G6PD activity and the expression of cyclin mRNAs, whereas it improved TM-3 cell viability by increasing mitochondrial membrane permeability and the activity of SDH. This could be one of mechanisms of DHEA exerts its biological function.
Dehydroepiandrosterone (DHEA) is a multifunctional steroid with a broad range of biological effects in humans and animals. DHEA can be converted to multiple oxygenated metabolites in the brain and peripheral tissues. The mechanisms by which DHEA exerts its effects are not well understood. However, evidence that the effects of DHEA are mediated by its oxygenated metabolites has accumulated. This paper will review the panel of oxygenated DHEA metabolites (7, 16 and 17-hydroxylated derivatives) including a number of 5α-androstane derivatives, such as epiandrosterone (EpiA) metabolites. The most important aspects of the oxidative metabolism of DHEA in the liver, intestine and brain are described. Then, this article reviews the reported biological effects of oxygenated DHEA metabolites from recent findings with a specific focus on cancer, inflammatory and immune processes, osteoporosis, thermogenesis, adipogenesis, the cardiovascular system, the brain and the estrogen and androgen receptors.
There is an increasing body of literature showing associations of organochlorine exposure with risk of diabetes and insulin resistance. Some studies suggest that associations differ by gender and that diabetes risk, in turn, may be affected by endogenous steroid hormones. This report examines the relationships of serum PCBs and endogenous hormones with history of diabetes in a cohort of persons previously employed at a capacitor manufacturing plant. A total of 118 women were post-menopausal with complete data, of whom 93 were not using steroid hormones in 1996, at the time of examination, which included a survey of exposure and medical history, height, weight and collection of blood and urine for measurements of lipids, liver function, hematologic markers and endogenous hormones. This analysis examines relationships of serum polychlorinated biphenyls (PCBs), work exposure and endogenous hormones with self-reported history of diabetes after control for potential confounders. All PCB exposure groups were significantly related to history of diabetes, but not to insulin resistance as measured by the homeostatic model assessment of insulin resistance (HOMA-IR) in non-diabetics. Diabetes was also independently and inversely associated with follicle stimulating hormone (FSH), dehydroepiandrosterone sulfate (DHEAS) and triiodothyronine (T3) uptake. HOMA-IR was positively associated with body mass index (BMI) and C-reactive protein (CRP) and inversely associated with sex hormone binding globulin (SHBG) and T3 uptake after control for PCB exposure. Possible biologic mechanisms are discussed. This study confirms previous reports relating PCB exposure to diabetes and suggests possible hormonal pathways deserving further exploration.
Brown adipose tissue (BAT) is well recognised to have an important role in the maintenance of body temperature in animals and human neonates, its thermogenic action affected by a tissue-specific uncoupling protein; fatty acid oxidation within the numerous brown adipocyte mitochondria is rendered inefficient leading to heat, rather than adenosine triphosphate (ATP), production. BAT was believed to show rapid involution in early childhood, leaving only vestigial amounts in adults. However, recent evidence suggests that its expression in adults is far more common than previously appreciated, with a higher likelihood of detection in women and leaner individuals. It is conceivable that BAT activity might reduce the risk of developing obesity since fat stores are used for thermogenesis, and a directed enhancement of adipocyte metabolism might have value in weight reduction. However, it is as yet unclear how such manipulation of BAT might be achieved; even in animal models, the control of thermogenic activity is incompletely understood. Even so, there is still much to interest the endocrinologist in BAT, with a range of hormones affecting adipocyte activity. This may either contribute to normal physiological function, or the phenotypical presentation of states of pathological hormone excess or deficiency. Thus, the gender differences in BAT distribution may be attributable to the differential effects of male and female sex hormones, whilst BAT expansion may drive the weight loss associated with catecholamine-producing phaeochromocytomas. These observations support an important influence of the endocrine system on BAT activity and offer new potential targets in the treatment of obesity.
Two natural 5-androstene steroid tetrols, androst-5-ene-3β,7β,16α,17β-tetrol (HE3177) and androst-5-ene-3α,7β,16α,17β-tetrol (HE3413), were discovered in human plasma and urine. These compounds had significant aqueous solubility, did not bind or transactivate steroid-binding nuclear hormone receptors, and were not immunosuppressive in murine mixed-lymphocyte studies. Both compounds appear to be metabolic end products, as they were resistant to primary and secondary metabolism. Both were orally bioavailable, and were very well tolerated in a two-week dose-intensive toxicity study in mice. Anti-inflammatory properties were found with exogenous administration of these compounds in rodent disease models of multiple sclerosis, lung injury, chronic prostatitis, and colitis.
Dehydroepiandrosterone (DHEA) administration has been shown to reduce accumulation of abdominal visceral fat and protect against insulin resistance in laboratory animals, but it is not known whether DHEA decreases abdominal obesity in humans. DHEA is widely available as a dietary supplement without a prescription.
To determine whether DHEA replacement therapy decreases abdominal fat and improves insulin action in elderly persons.
Randomized, double-blind, placebo-controlled trial conducted in a US university-based research center from June 2001 to February 2004.
Fifty-six elderly persons (28 women and 28 men aged 71 [range, 65-78] years) with age-related decrease in DHEA level.
Participants were randomly assigned to receive 50 mg/d of DHEA or matching placebo for 6 months.
The primary outcome measures were 6-month change in visceral and subcutaneous abdominal fat measured by magnetic resonance imaging and glucose and insulin responses to an oral glucose tolerance test (OGTT).
Of the 56 men and women enrolled, 52 underwent follow-up evaluations. Compliance with the intervention was 97% in the DHEA group and 95% in the placebo group. Based on intention-to-treat analyses, DHEA therapy compared with placebo induced significant decreases in visceral fat area (-13 cm2 vs +3 cm2, respectively; P = .001) and subcutaneous fat (-13 cm2 vs +2 cm2, P = .003). The insulin area under the curve (AUC) during the OGTT was significantly reduced after 6 months of DHEA therapy compared with placebo (-1119 muU/mL per 2 hours vs +818 muU/mL per 2 hours, P = .007). Despite the lower insulin levels, the glucose AUC was unchanged, resulting in a significant increase in an insulin sensitivity index in response to DHEA compared with placebo (+1.4 vs -0.7, P = .005).
DHEA replacement could play a role in prevention and treatment of the metabolic syndrome associated with abdominal obesity.
In human beings of both sexes, dehydroepiandrosterone sulfate (DHEAS) circulating in blood is mostly an adrenally secreted steroid whose serum concentration (in the micromolar range and 30-50% higher in men than in women) decreases with age, toward approximately 20-10% of its value in young adults during the 8th and 9th decades. The mechanism of action of DHEA and DHEAS is poorly known and may include partial transformation into sex steroids, increase of bioavailable insulin-like growth factor 1, and effects on neurotransmitter receptors. Whether there is a cause-to-effect relationship between the decreasing levels of DHEAS with age and physiological and pathological manifestations of aging is still undecided, but this is of obvious theoretical and practical interest in view of the easy restoration by DHEA administration. Here we report on 622 subjects over 65 years of age, studied for the 4 years since DHEAS baseline values had been obtained, in the frame of the PAQUID program, analyzing the functional, psychological, and mental status of a community-based population in the south-west of France. We confirm the continuing decrease of DHEAS serum concentration with age, more in men than in women, even if men retain higher levels. Significantly lower values of baseline DHEAS were recorded in women in cases of functional limitation (Instrumental Activities of Daily Living), confinement, dyspnea, depressive symptomatology, poor subjective perception of health and life satisfaction, and usage of various medications. In men, there was a trend for the same correlations, even though not statistically significant in most categories. No differences in DHEAS levels were found in cases of incident dementia in the following 4 years. In men (but not in women), lower DHEAS was significantly associated with increased short-term mortality at 2 and 4 years after baseline measurement. These results, statistically established by taking into account corrections for age, sex, and health indicators, suggest the need for further careful trials of the administration of replacement doses of DHEA in aging humans. Indeed, the first noted results of such "treatment" are consistent with correlations observed here between functional and psychological status and endogenous steroid serum concentrations.
Human brown pre-adipocytes were immortalized by microinjection of the genes encoding simian virus 40 T and t antigens under the control of the human vimentin promotor. The transfected pre-adipocytes were cultured for several months with no loss of their morphological characteristics. These cells accumulate lipids and differentiate into adipocytes when treated with insulin, triiodothyronine and dexamethazone. The mRNA of various adipocyte markers was detected by reverse transcriptase-polymerase chain reaction analysis, including hormone-sensitive lipase, lipoprotein lipase, adipsin, glucose transporters 1 and 4, the uncoupling protein (specific of brown adipocytes), and leptin, the product of the ob gene. Pharmacological analyses indicated that the beta3-adrenoceptor is the predominant beta-adrenoceptor subtype in PAZ6 cells and that this receptor subtype is functionally coupled to adenylate cyclase and lipolysis. The immortalization of human adipocytes will permit pharmacological analysis of the human beta3-adrenoceptor function in adipose cells and will allow detailed studies of human adipocyte differentiation.
Troglitazone (a thiazolidinedione that improves insulin resistance) lowers elevated androgen concentrations in women with polycystic ovarian syndrome. In this study, we assessed the direct effects of troglitazone on steroidogenesis in porcine granulosa cells. Troglitazone inhibited progesterone production in a dose- and time-dependent manner (earliest effects at 4 h, maximum at 24 h) without affecting cell viability. Progesterone production was also inhibited by troglitazone in the presence of 25-hydroxycholesterol, indicating that the drug does not affect intracellular cholesterol transport. Troglitazone also inhibited FSH- and forskolin-stimulated progesterone secretion. The reduced progesterone production was accompanied by marked elevations of pregnenolone concentrations, suggesting inhibition of 3beta-hydroxysteroid dehydrogenase (3beta-HSD). The activity of 3beta-HSD in troglitazone-treated granulosa cells was decreased by more than 60%, compared with controls after 24 h. Troglitazone did not affect aromatase activity in porcine granulosa cells. In summary, troglitazone has direct effects on porcine granulosa cell steroidogenesis. The drug specifically inhibits 3beta-HSD activity, resulting in impaired progesterone production. The clinical relevance of this direct in vitro effect on steroidogenesis needs further investigation.
The age-related decline in serum dehydroepiandrosterone (DHEA) and its sulfated ester (DHEA-S) has suggested that a relative deficiency of these steroids may be causally related to the development of chronic diseases generally associated with aging, including insulin resistance, obesity, cardiovascular disease, cancer, reductions of the immune defense, depression and a general deterioration in the sensation of well-being. The numerous studies which have focused on the link between DHEA and cardiovascular disease have generally been inconsistent, generating much debate and controversy on this issue. The present article is an analysis of studies on the relationship between endogenous DHEA or DHEA-S, obesity and cardiovascular disease risk, as well as DHEA treatment studies. Elevated plasma levels of free DHEA are associated with reduced obesity in both men and women, and with smaller abdominal body fat accumulations in men. However, contradictory results have been reported regarding the relationships between the sulfate ester DHEA-S and adiposity. Age differences in the populations studied may have been a confounding factor in these associations. On the other hand, DHEA-S level is not a predictor of cardiovascular disease endpoints in women, and appears to be a relatively weak one in men. DHEA intervention studies suggest that the effects of DHEA on serum lipids are, at best, modest or non-significant. The uncertainty as to whether endogenous and exogenous DHEA should be considered cardioprotective is related to discrepancies in the literature on this topic. Several studies may have been plagued by methodological problems such as low power, unreliable analytical methods, confounding factors or other differences in the populations studied. As a consequence, the original reports demonstrating dramatic effects of either endogenous or exogenous DHEA on cardiovascular disease risk have never been replicated. We propose that the effects of DHEA on cardiovascular disease risk (either favorable or unfavorable) should be considered to be much more modest than previously believed.
Expression analysis by reverse transcriptase (RT)-PCR indicates that human adipose tissue is not likely to perform de novo synthesis of steroid hormones from cholesterol because the mRNAs of cytochromes P450scc and P450c17, and of the steroidogenic-related proteins, steroidogenic acute regulatory protein and steroidogenic factor 1, were not detected. Instead, our data support an intracrine role of adipose tissue, in which adrenal dehydroepiandrosterone sulfate (DHEA-S), the most abundant circulating androgen in man, is selectively uptaken, desulfated, and converted into bioactive androgens and estrogens. Three organic anion-transporting polypeptides-B, -D, and -E, presumably involved in DHEA-S transmembrane transport, were demonstrated at the mRNA level. While sulfotransferase expression was not found, the occurrence of steroid sulfatase (STS), converting DHEA-S to DHEA, was established at the mRNA, protein and catalytic activity levels. The 5'-rapid amplification of cDNA ends analysis showed that STS transcription in adipose tissue is regulated by the use of two promoters which differ from the prevalent placental one. The adipose transcripts contain a distinct untranslated first exon, 0a or 0b, followed by a common partially translated exon 1b, and nine other exons that are also shared by the main placental transcript. The presence of an upstream open reading frame in the new transcript variants could lead to an N-terminal divergence restricted to the cleavable signal peptide and thus not interfering with the catalytic activity of the mature STS protein. The adipose transcripts are also present in the placenta as minor isoforms. Western blotting revealed the characteristic approximately 64 kDa band of STS in both the placenta and adipose tissue. The specific enzymatic activity of STS in adipocytes was 118 pmol/10(6) cells per hour, about 50-100 times lower than in the placenta. A similar rate of [3H] DHEA-S uptake plus desulfation was measured in preadipocytes and adipocytes, equivalent to 40-45 pmol/10(6) cells per hour. Thus, an excessive accumulation of fat may out-compete other peripheral organs that are also dependent on intracrine DHEA-S utilization, especially when the adrenal production is low or declining with aging.
A growing body of studies has demonstrated the inverse relationship between DHEA-sulfate (DHEA-S) and the pathological alterations associated with the metabolic syndrome. However, the mechanism by which DHEA-S treatment operates has not been elucidated completely. Adiponectin, an adipose-specific protein, is thought to have anti-diabetic and anti-atherosclerotic properties. Because fat depots differ in the impact of their relationship with the undesirable consequences of obesity, the aim of the present study was to investigate the effect of DHEA-S on adiponectin expression in both s.c. and visceral tissues in a morbidly obese population.
We studied the in vitro expression of the adiponectin gene from paired biopsies of human visceral and s.c. adipose tissue, obtained from men and women (body mass index = 48.68+/- 7.43 kg/m2). Adipocytes were incubated for 24 h with or without DHEA-S. Adiponectin mRNA was measured by reverse transcription-quantitative PCR.
In this population, DHEA-S plasma values were 141 +/- 105 microg/100 ml. Serum adiponectin values were under normal ranges. In basal conditions, s.c. tissue expressed higher amounts (58%) of adiponectin mRNA than visceral tissue (P = 0.027). Adiponectin expression was differentially regulated in the two depots by DHEA-S. There was a significant increase in adiponectin expression specifically in the visceral tissue (P = 0.020), but no significant effect of DHEA-S on the s.c. tissue (P = 0.738).
In the present study, for the first time in humans, we have shown that DHEA-S treatment is a strong upregulator of adiponectin gene expression in omental adipocytes, suggesting that the positive effects observed by DHEA-S treatment in humans suffering from metabolic syndrome could be exerted through overexpression of adiponectin in the visceral depot.
Thyrotropin receptor (TSHR) expression is upregulated in the orbits of patients with Graves ophthalmopathy (GO), most of whom have TSHR-stimulating antibodies. The authors investigated the biological effects of TSHR activation in vitro in adipose tissue, the site of orbital TSHR expression.
Activating mutant TSHR (TSHR*) or wild-type (WT) was introduced into human orbital preadipocytes using retroviral vectors. Their proliferation (Coulter counting), basal cAMP accumulation (radioimmunoassay), and spontaneous and peroxisome proliferator-activated receptor (PPARgamma)-induced adipogenesis (quantitative oil red O staining) were assessed and compared with those of nonmodified cells. QRT-PCR was used to measure transcripts of CCAT/enhancer binding protein (C/EBP)beta, PPARgamma, and lipoprotein lipase (LPL; early, intermediate, and late markers of adipogenesis) and for uncoupling protein (UCP)-1 (brown adipose tissue [BAT]).
Expression of TSHR* significantly inhibited the proliferation of preadipocytes and produced an increase in unstimulated cAMP of 200% to 600%. Basal lipid levels were significantly increased in TSHR* (127%-275%) compared with nonmodified (100%) or WT-expressing (104%-187%) cells. This was accompanied by 2- to 10-fold increases in early-intermediate markers and UCP-1 transcripts (2- to 8-fold); LPL was at the limit of detection. In nonmodified cells, adipogenesis produced significant increases in transcripts of all markers, including LPL (approximately 30-fold). This was not the case in TSHR*-expressing cells, which also displayed 67% to 84% reductions in lipid levels.
TSHR activation stimulates early differentiation (favoring BAT formation?) but renders preadipocytes refractory to PPARgamma-induced adipogenesis. In neither case did lipid-containing vacuoles accumulate, suggesting that terminal stages of differentiation were inhibited.
Dehydroepiandrosterone (DHEA) and DHEA sulfate (DHEAS) are the major circulating adrenal steroids and substrates for peripheral sex hormone biosynthesis. In Addison's disease, glucocorticoid and mineralocorticoid deficiencies require lifelong replacement, but the associated near-total failure of DHEA synthesis is not typically corrected.
In a double-blind trial, we randomized 106 subjects (44 males, 62 females) with Addison's disease to receive either 50 mg daily of micronized DHEA or placebo orally for 12 months to evaluate its longer-term effects on bone mineral density, body composition, and cognitive function together with well-being and fatigue.
Circulating DHEAS and androstenedione rose significantly in both sexes, with testosterone increasing to low normal levels only in females. DHEA reversed ongoing loss of bone mineral density at the femoral neck (P < 0.05) but not at other sites; DHEA enhanced total body (P = 0.02) and truncal (P = 0.017) lean mass significantly with no change in fat mass. At baseline, subscales of psychological well-being in questionnaires (Short Form-36, General Health Questionnaire-30), were significantly worse in Addison's patients vs. control populations (P < 0.001), and one subscale of SF-36 improved significantly (P = 0.004) after DHEA treatment. There was no significant benefit of DHEA treatment on fatigue or cognitive or sexual function. Supraphysiological DHEAS levels were achieved in some older females who experienced mild androgenic side effects.
Although further long-term studies of DHEA therapy, with dosage adjustment, are desirable, our results support some beneficial effects of prolonged DHEA treatment in Addison's disease.
Troglitazone (a thiazolidinedione that improves insulin resistance) lowers elevated androgen concentrations in women with polycystic ovarian syndrome. In this study, we assessed the direct effects of troglitazone on steroidogenesis in porcine granulosa cells. Troglitazone inhibited progesterone production in a dose- and time-dependent manner (earliest effects at 4 h, maximum at 24 h) without affecting cell viability. Progesterone production was also inhibited by troglitazone in the presence of 25-hydroxycholesterol, indicating that the drug does not affect intracellular cholesterol transport. Troglitazone also inhibited FSH- and forskolin-stimulated progesterone secretion. The reduced progesterone production was accompanied by marked elevations of pregnenolone concentrations, suggesting inhibition of 3β-hydroxysteroid dehydrogenase (3β-HSD). The activity of 3β-HSD in troglitazone-treated granulosa cells was decreased by more than 60%, compared with controls after 24 h. Troglitazone did not affect aromatase activity in porcine granulosa cells. In summary, troglitazone has direct effects on porcine granulosa cell steroidogenesis. The drug specifically inhibits 3β-HSD activity, resulting in impaired progesterone production. The clinical relevance of this direct in vitro effect on steroidogenesis needs further investigation.
Insulin resistance is the cornerstone for the development of non-insulin-dependent diabetes mellitus (NIDDM). Free fatty acids (FFAs) cause insulin resistance in muscle and liver and increase hepatic gluconeogenesis and lipoprotein production and perhaps decrease hepatic clearance of insulin. It is suggested that the depressing effect of insulin on circulating FFA concentration is dependent on the fraction derived from visceral adipocytes, which have a low responsiveness to the antilipolytic effect of insulin. Elevated secretion of cortisol and/or testosterone induces insulin resistance in muscle. This also seems to be the case for low testosterone concentrations in men. In addition, cortisol increases hepatic gluconeogenesis. Cortisol and testosterone have "permissive" effects on adipose lipolysis and therefore amplify lipolytic stimulation; FFA, cortisol, and testosterone thus have powerful combined effects, resulting in insulin resistance and increased hepatic gluconeogenesis. All these factors promoting insulin resistance are active in abdominal visceral obesity, which is closely associated with insulin resistance, NIDDM, and the "metabolic syndrome." In addition, the endocrine aberrations may provide a cause for visceral fat accumulation, probably due to regional differences in steroid-hormone-receptor density. In addition to the increased activity along the adrenocorticosteroid axis, there also seem to be signs of increased activity from the central sympathetic nervous system. These are the established endocrine consequences of hypothalamic arousal in the defeat and defense reactions. There is some evidence that suggests an increased prevalence of psychosocial stress factors is associated with visceral distribution of body fat. Therefore, it is hypothesized that such factors might provide a background not only to a defense reaction and primary hypertension, suggested previously, but also to a defeat reaction, which contributes to an endocrine aberration leading to metabolic aberrations and visceral fat accumulation, which in turn leads to disease.
A microsomal preparation of human prostatic tissue was used to study the kinetics of interaction of steroid 5alpha-reductase with finasteride, a known 5alpha-reductase inhibitor. This molecule has been reported to reversibly bind 5alpha-reductase in a competitive manner to testosterone with a K(i) value in the 10 nM range. The results presented in this paper show that enzyme-inhibitor complex formation does not take place instantaneously as assumed in previous studies. At neutral pH and 37-degrees-C, the association of enzyme with inhibitor is governed by a rate constant, k(on), of 2.7 X 10(5) M-1 s-1. This low k(on) value, in combination with the high energy of activation of the association reaction (150 kJ mol-1), indicates that the association process is not diffusion controlled and may proceed through intermediate steps. However, such an intermediate was not detected kinetically under the inhibitor concentrations investigated. We therefore conclude that the equilibrium dissociation constant, K(i)*, for the initial binding of the enzyme to the inhibitor is higher than 1.5 X 10(-7) M. Even at inhibitor concentrations as low as 1 nM, the reaction was completely displaced to the EI complex and no residual activity detected once the equilibrium was reached. Hence, the interaction between finasteride and 5alpha-reductase can also be characterized by a very low overall equilibrium dissociation constant (K(i) << 10(-9) M), at least 1 order of magnitude lower than previously reported values. pH profiles of k, the pseudo-first-order rate constant for the association of enzyme with inhibitor, and V(m)/K(m) were similar, indicating that the same ionizable groups are involved in the interaction of the enzyme with both testosterone and finasteride. Our results show that finasteride can efficiently compete with testosterone for the binding to 5alpha-reductase since we demonstrate that K(i) << K(m). The data presented in this paper support what is observed in vivo, predicting that pseudoirreversible inhibition of steroid 5alpha-reductase will take place in the presence of testosterone.
Dehydroepiandrosterone sulfate (DS), 16α-hydroxydehydroepiandrosterone sulfate (16α-OH-DS) and 16α-hydroxydehydroepiandrosterone (16α-OH-D) were measured in cord plasma of five anencephalic fetuses with histologically proven hypoplasia of the fetal zone of the adrenal cortex. DS was determined by the Zimmermann reaction on paper as described previously by us, the 16α-hydroxylated compounds by a modification of the method of Katz. These hormones were also measured in antecubital venous blood of the mothers of these fetuses. For comparison normal pregnant women and normal fetuses were studied. Neither 16α-OH-D nor 16α-OH-DS could be detected in peripheral blood of mothers bearing anencephalic or normal fetuses. In the former group, all DS levels (M±s = 93±31 μg%) were within the normal range. 16α-OH-D, 16α-OH-DS, or DS could not be detected in the cord plasm of anencephalic fetuses. If these steroids were present, their concentrations (< 10–25 μg DS%, < 9.5–36 μg 16α-OH-DS% and < 4 μg 16α-OH-D%) were markedly reduced as compared with normal fetuses for which values are given. Evidence is presented for the nature of 16α-OH-DS as a monosulfate, presumbly the 3β-sulfate. The values reported for 16α-OH-DS are not corrected for losses; the corrected values would be about three times higher. It is hypothesized from this study that the decrease of 16α-OH-D, 16α-OH-DS, and DS in blood of anencephalic fetuses is due to the hypoplasia of the fetal zone of the adrenal cortex, and is the major cause of the low excretion of estrogens, especially estriol, in the maternal urine.
Patients with Addison's disease and hypopituitarism have increased mortality, chiefly related to vascular disease. Both diseases are characterized by dehydroepiandrosterone (DHEA) deficiency, yet this is not usually corrected. It is unclear whether treatment of these conditions with DHEA improves cardiovascular risk.
The aim of the study was to evaluate the effects of DHEA on arterial stiffness and endothelial function in subjects with Addison's disease and hypopituitarism.
Forty subjects (20 with Addison's disease, 20 with panhypopituitarism) were assigned to consecutive 12-wk treatment periods of DHEA 50 mg or placebo in a randomized, double-blind, crossover design separated by an 8-wk washout.
Primary outcome parameters were measures of arterial stiffness [augmentation index, central blood pressure, brachial and aortic pulse wave velocity (PWV)] and endothelial function. Serum androgens, anthropometry, and metabolic biochemistry (lipids, homeostasis model of assessment for insulin resistance, high sensitivity C-reactive protein, adiponectin, plasminogen activator inhibitor-1) were also assessed.
Despite normalization of DHEA sulfate, androstenedione, and testosterone (females), DHEA replacement did not affect augmentation index, aortic PWV, brachial PWV, central blood pressure, or endothelial function. DHEA did not affect any anthropometric or metabolic measures, apart from a small reduction in high-density lipoprotein cholesterol (-0.08 mmol/liter; P = 0.007; 95% confidence interval for the difference, -0.13 to -0.02 mmol/liter).
Short-term DHEA supplementation does not significantly affect measures of arterial stiffness or endothelial function in patients with adrenal insufficiency.
Insulin resistance is the cornerstone for the development of non-insulin-dependent diabetes mellitus (NIDDM). Free fatty acids (FFAs) cause insulin resistance in muscle and liver and increase hepatic gluconeogenesis and lipoprotein production and perhaps decrease hepatic clearance of insulin. It is suggested that the depressing effect of insulin on circulating FFA concentration is dependent on the fraction derived from visceral adipocytes, which have a low responsiveness to the antilipolytic effect of insulin. Elevated secretion of cortisol and/or testosterone induces insulin resistance in muscle. This also seems to be the case for low testosterone concentrations in men. In addition, cortisol increases hepatic gluconeogenesis. Cortisol and testosterone have "permissive" effect on adipose lipolysis and therefore amplify lipolytic stimulation; FFA, cortisol, and testosterone thus have powerful combined effects, resulting in insulin resistance and increased hepatic gluconeogenesis. All these factors promoting insulin resistance are active in abdominal visceral obesity, which is closely associated with insulin resistance, NIDDM, and the "metabolic syndrome." In addition, the endocrine aberrations may provide a cause for visceral fat accumulation, probably due to regional differences in steroid-hormone-receptor density. In addition to the increased activity along the adrenocorticosteroid axis, there also seem to be signs of increased activity from the central sympathetic nervous system. These are the established endocrine consequences of hypothalamic arousal in the defeat and defense reactions. There is some evidence that suggests an increased prevalence of psychosocial stress factors is associated with visceral distribution of body fat. Therefore, it is hypothesized that such factors might provide a background not only to a defense reaction and primary hypertension, suggested previously, but also to a defeat reaction, which contributes to an endocrine aberration leading to metabolic aberrations and visceral fat accumulation, which in turn leads to disease.
333 consecutive patients with hypopituitarism diagnosed between 1956 and 1987 were retrospectively examined. The patients had been given routine replacement therapy. The overall mortality was higher than in an age and sex matched population. Deaths from vascular disorders were also significantly increased (60 [40 male, 20 female] versus 30.8 expected [23.5, 7.4 female]). The hazard function for vascular death was independent of age at diagnosis, time after diagnosis, calendar year of diagnosis, gender, degree of pituitary insufficiency, hypertension, and diabetes mellitus. Mortality risk was raised irrespective of whether hypopituitarism was due to pituitary adenoma or secondary to other diseases. 7 patients (3 male, 4 female) died from malignant diseases (expected 10.1 and 4.1, respectively). These observations indicate that life expectancy is shortened in patients with hypopituitarism. Growth-hormone deficiency could be a factor in this increased mortality from cardiovascular disease.
Dehydroepiandrosterone (DHEA) and certain structural analogues block the differentiation of 3T3-L1 mouse embryo fibroblasts to adipocytes. These steroids also are potent uncompetitive inhibitors of mammalian glucose-6-phosphate dehydrogenases (G6PDs). We provide direct evidence that treatment of the 3T3-L1 cells with DHEA and its analogues results in intracellular inhibition of G6PD, which is associated with the block of differentiation: (i) Levels of 6-phosphogluconate and other products of the pentose phosphate pathway are decreased; (ii) the magnitude of these decreases depends on the potency of steroids as inhibitors of G6PD and on concentration and duration of exposure, and it is accompanied by a proportionate block of differentiation; (iii) in cells exposed to 16 alpha-bromoepiandrosterone (a more potent inhibitor of G6PD than DHEA) at concentrations that block differentiation, introduction of exogenous 6-phosphogluconate in liposomes raises the levels of 6-phosphogluconate and other products of the pentose phosphate pathway and partially relieves the steroid block of cell growth and differentiation.
The contribution of obesity to cardiovascular risk has not been adequately appreciated because of a failure to recognize the involvement of upper-body predominance of body weight with hypertension, diabetes, and hypertriglyceridemia even in the absence of significant overall obesity. This article examines the evidence that upper-body obesity, as usually induced by caloric excess in the presence of androgens, mediates these problems by way of hyperinsulinemia. Because of these interrelationships, there is a need to identify and prevent upper-body obesity or, failing that, to provide therapies that will control the associated problems without aggravating hyperinsulinemia.
Dehydroepiandrosterone (3 beta-hydroxy-5-androsten-17-one; DHEA) and related steroids have widespread protective effects against spontaneous and chemically induced tumors, suppress weight gain without affecting food intake, and depress lipogenesis. We have observed that DHEA and 16 alpha-bromoepiandrosterone (16 alpha-bromo-3 beta-hydroxy-5 alpha-androstan-17-one) block the conversion to adipocytes of the 3T3-L1 and 3T3-F442A mouse embryo fibroblast clones. The arrest of lipogenic conversion was assessed by measurements of lipid biosynthesis and the specific activity of cytosolic glycerol-3-phosphate dehydrogenase. In the presence of 215 microM DHEA or 30 microM 16 alpha-bromoepiandrosterone, the increase in glycerol-3-phosphate activity was only 50% of that of fully differentiated control cells. The blocking effects were concentration dependent and were observed only if the differentiation stimuli and the blocking steroid were present simultaneously. Concentrations of these steroids that almost completely blocked conversion to adipocytes were not cytotoxic. Although the relation between structure and blocking activity of steroids is complicated by metabolism of DHEA in these cultures, a strong correlation exists between the structural requirements for blocking differentiation and for inhibition of glucose-6-phosphate dehydrogenase. The 3T3-L1 and 3T3-F442A preadipocyte clones are, therefore, appropriate and convenient model systems for the analysis of the mechanism of the anticarcinogenic effects of DHEA and related steroids.
Dehydroepiandrosterone sulfate (DS), 16α-hydroxydehydroepiandrosterone sulfate (16α-OH-DS) and 16α-hydroxydehydroepiandrosterone (16α-OH-D) were measured in mixed cord plasma and maternal plasma of 6 pregnant women who were treated with prednisone and hydrocortisone succinate during pregnancy and labor. All three steroid hormones were markedly lowered in the fetal blood. (DS: M = 53 μ%, 16α-OH-DS: M = 45 μg%, 16α-OH-D = < 6 μg%). The level of these steroids appears to vary inversely with the amount of corticoids given to the mother. In the maternal blood DS was either not measurable or very low (range < 8-29 μg%) as compared with normal values for untreated pregnant women. No 16α-OH-D or 16α-OH-DS could be detected in the p lasma of these patients. Maternal urinary estriol, estrone, and estradiol were also decreased in three of the cases studied. It is hypothesized that the decrease of urinary estrogens in these patients is mainly due to a suppression of the release of C19-steroid hormones by the maternal and fetal adrenal; the suppression of the fetal adrenal by exogenous corticoids being of major importance. It is pointed out that in cases with corticoid treatment during pregnency a low urinary estrogen excretion does not need to interfere with the development of pregnancy and does not reflect a hazard to the fetus.
The uptake and metabolism of various steroids in adipose tissue were studied using both in vitro and in vivo techniques. The in vitro uptake of progesterone and testosterone (60%) was found to be much higher than the uptake of cortisol and estriol (13%). In vivo, the uptake of testosterone, androstenedione, estrone and estradiol by the total adipose mass was much greater in obese patients than in non obese individuals. Estrone and estradiol were found to be interconvertible following incubation with human adipose tissue slices. In vitro, progesterone was metabolized to a variety of compounds, with 20α dihydroprogesterone being the major metabolite. No conversion of cholesterol or cholesterol sulfate to pregnenolone or pregnenolone sulfate could be demonstrated in the brown adipose tissue of a newborn infant. In human adult subcutaneous adipose tissue, there was no in vitro conversion of progesterone to testosterone, and no aromatization of androstenedione or testosterone labeled with 14C was detected. There was also no in vivo interconversion of estrone and estradiol in the mesenteric adipose tissue of the dog. In human subcutaneous adipose tissue, the in vivo interconversion of testosterone and androstenedione was demonstrated.
Using radioimmunological methods, levels of cortisol, dehydroepiandrosterone, androstenedione, testosterone, oestrogens (oestradiol + oestrone), progesterone and 17 alpha-hydroxyprogesterone were determined in adipose tissue and peripheral blood obtained during surgical treatment of patients with non-endocrine diseases. The steroid content of human adipose tissue was observed to be extremely high relative to that in the general circulation, giving a tissue/serum ratio of 0.4 to 13.2. The concentration of steroids decreased in the following order: dehydroepiandrosterone greater than cortisol greater than androstenedione greater than progesterone greater than testosterone greater than 17 alpha-hydroxyprogesterone greater than oestradiol + oestrone. This sequence is different from that found in blood. When anthropometric variables were taken into consideration, the adipose tissue mass of severely obese subjects contained a steroid pool far greater than that in the total blood volume.
Plasma concentrations of 5-androstene-3 beta,17 beta-diol (ADIOL) dehydroepiandrosterone (DHA) dehydroepiandrosterone sulphate (DHAS) and cortisol were measured by radioimmunoassay in a group of women aged between 27 and 88 years of age. There was a significant negative correlation with increased age for all three adrenal androgens but not for cortisol. The decrease in adrenal androgens was not related to an excessive divergence from ideal body weight. There was a highly significantly positive correlation between plasma concentrations of all three adrenal androgens which supports a metabolic interrelationship.
In a cross-sectional study, serum dehydroepiandrosterone sulfate (DS) concentrations were measured in 981 men and 481 women, aged 11-89, yr. The resulting data were asymetrically distributed and were normalized by logarithmic transformation and analyzed by 5-yr age grouping (e.g. 15-19 yr, 20-24 yr, etc.). The DS concentration peaked at age 20-24 yr in men (logarithmic mean, 3470 ng/ml) and at age 15-19 yr in women (log mean, 2470 ng/ml). Mean values then declined steadily in both sexes (log mean at greater than 70 yr of age, 670 ng/ml in men and 450 ng/ml in women) and were significantly higher in men than women at ages from 20-69 yr. Analysis of 517 randomly selected sera (from women) which had been stored frozen for 10-15 yr gave results indistinguishable from values obtained from fresh specimens. In a supplementary study, a longitudinal analysis of weekly specimens from 4 normal men, aged 36-59 yr, revealed individual variability (mean coefficient of variation, 19%) and failed to demonstrate any monthly, seasonal, or annual rhythmicity. Based on the above analyses, a table of normal serum DS ranges for adult men and women is presented for use as a clinical reference.
A longitudinal population study of 1462 women aged 38-60 was carried out in Gothenburg, Sweden, in 1968-9. In univariate analysis the ratio of waist to hip circumference showed a significant positive association with the 12 year incidence of myocardial infarction, angina pectoris, stroke, and death. The association with incidence of myocardial infarction remained in multivariate analysis and was independent of age, body mass index, smoking habit, serum cholesterol concentration, serum triglyceride concentration, and systolic blood pressure. The relation between the ratio of waist to hip circumference and the end points of myocardial infarction, angina pectoris, stroke, and death was stronger than for any other anthropometric variable studied.
A microsomal preparation of human prostatic tissue was used to study the kinetics of interaction of steroid 5 alpha-reductase with finasteride, a known 5 alpha-reductase inhibitor. This molecule has been reported to reversibly bind 5 alpha-reductase in a competitive manner to testosterone with a Ki value in the 10 nM range. The results presented in this paper show that enzyme-inhibitor complex formation does not take place instantaneously as assumed in previous studies. At neutral pH and 37 degrees C, the association of enzyme with inhibitor is governed by a rate constant, kon, of 2.7 x 10(5) M-1 s-1. This low kon value, in combination with the high energy of activation of the association reaction (150 kJ mol-1), indicates that the association process is not diffusion controlled and may proceed through intermediate steps. However, such an intermediate was not detected kinetically under the inhibitor concentrations investigated. We therefore conclude that the equilibrium dissociation constant, Ki*, for the initial binding of the enzyme to the inhibitor is higher than 1.5 x 10(7) M. Even at inhibitor concentrations as low as 1 nM, the reaction was completely displaced to the EI complex and no residual activity detected once the equilibrium was reached. Hence, the interaction between finasteride and 5 alpha-reductase can also be characterized by a very low overall equilibrium dissociation constant (Ki < 10(-9) M), at least 1 order of magnitude lower than previously reported values.(ABSTRACT TRUNCATED AT 250 WORDS)
3 beta-Hydroxysteroid dehydrogenase-isomerase (3 beta-HSD-I) activity in the pig testis is responsible for the conversion of dehydroepiandrosterone (DHA) to 4-androstenedione and also for the conversion of 5,16-androstadien-3 beta-ol (andien-beta) to 4, 16-androstadien-3-one (dienone). Therefore, 3 beta-HSD-I plays an essential role in the biosynthesis of hormonally and pheromonally active steroids. Previous studies from this laboratory have suggested that the 3 beta-HSD-I reactions in the androgen and 16-androstene biosynthetic pathways may be catalysed by different enzymes with selective substrate specificities [3, 4]. The aim of the present studies was to investigate the reactions further by examining the effects of two classical steroidal inhibitors of 3 beta-HSD-I, trilostane (WIN 24540) and cyanoketone (WIN 19578), on the kinetic parameters of the 3 beta-HSD-I reactions in immature (< 3 weeks) pig testis microsomes. In kinetic analyses of the conversion of DHA to 4-androstenedione, both trilostane and cyanoketone caused increases in the Km(app) for DHA which at the highest concentration used, were 15-fold the control Km(app) of 1.4 mumol/l. No effect on the Vmax(app) (6.55 +/- 0.74 nmol/h/mg protein) was observed, demonstrating that competitive inhibition was evident. Slope and intercept replots confirmed the competitive nature of the inhibition and Ki(app) values of 0.16 mumol/l for trilostane and 0.20 mumol/l for cyanoketone were respectively 9 and 7-fold lower than the Km(app) value. In contrast, trilostane and cyanoketone had no effect on the Km(app) for andien-beta (0.26 mumol/l). The Vmax(app) (1.12 nmol/h/mg protein) was decreased by 40-50% only by trilostane at the highest concentration used, demonstrating a very low affinity for the andien-beta active site. Ki(app) values for trilostane and cyanoketone, obtained from slope and intercept replots were, respectively 1.1 and 1.6 mumol/l, which were 4 and 6-fold greater than the Km(app) for andien-beta. Therefore, trilostane and cyanoketone were powerful competitive inhibitors of the conversion of DHA to 4-androstenedione but were weak non-competitive inhibitors of the conversion of andien-beta to dienone. The selective effects of trilostane and cyanoketone on the 3 beta-HSD-Is involved in the androgen and 16-androstene biosynthetic pathways strongly suggest that the reactions are catalysed by separate enzymes, or at least separate, non-interacting active sites on a single enzyme.
To determine if chronic administration of a low level of dehydroepiandrosterone-sulfate (DHEAS) (10 micrograms/ml drinking water) attenuates adiposity in male Osborne-Mendel rats fed low-fat (11% of kcals) vs high fat (46% of kcals) diets.
Rats were randomly assigned to one of four treatment groups for 6 wk in this 2 x 2 factorial study. The main effects tested were diet (low vs high fat) and DHEAS (- or +).
Male Osborne-Mendel rats (initial body wt approximately 265 g).
Adipocyte mass, size and number from two major fat depots (retroperitoneal, epididymal); mass of one subcutaneous adipose depot (inguinal); serum levels of triglycerides, insulin, glucose and DHEAS; brown adipose tissue (BAT) mass; body weight gain, food and water consumption, and residual carcass composition.
DHEAS treatment had no effect on weight gain, food consumption or water intake. DHEAS-treated rats fed the high-fat diet had smaller fat pads containing fewer adipocytes and less carcass lipid than the non DHEAS-treated rats fed the high-fat diet. In contrast, DHEAS-treated rats fed the low-fat diet had similar levels of adipose tissue mass and cellularity compared to control animals fed the low-fat diet.
Administration of a low dose of DHEAS (10 micrograms/ml or 0.8 mg/kg body wt/d) in the drinking water of young male Osborne-Mendel rats fed a high-fat diet for 6 wk reduced carcass lipid, fat depot mass and retroperitoneal and epididymal adipocyte number compared to their high-fat-fed cohorts. In this study, the antiobesity effects of DHEAS were specific to the level of dietary fat used.
Visceral obesity is frequently associated with muscle insulin resistance. Rats fed a high-fat diet rapidly develop obesity and insulin resistance. Dehydroepiandrosterone (DHEA) has been reported to protect against the development of obesity. This study tested the hypothesis that DHEA protects against the increase in visceral fat and the development of muscle insulin resistance induced by a high-fat diet in rats. Feeding rats a diet providing 50% of the energy as fat for 4 wk resulted in a twofold greater visceral fat mass and a 50% lower rate of maximally insulin-stimulated muscle 2-deoxyglucose (2-DG) uptake compared with controls. Rats fed the high-fat diet plus 0.3% DHEA were largely protected against the increase in visceral fat (+ 11.3 g in high fat vs. + 2.9 g in high fat plus DHEA, compared with controls) and against the decrease in insulin-stimulated muscle 2-DG uptake (0.94 +/- 0.15 mumol.ml-1.20 min-1, controls; 0.46 +/- 0.06 mumol.ml-1.20 min-1, high-fat diet; 0.78 +/- 0.07 mumol.ml-1.20 min-1, high fat + DHEA). DHEA did not affect food intake. These results show that DHEA has a protective effect against accumulation of visceral fat and development of muscle insulin resistance in rats fed a high-fat diet.
Adipose tissue is a site of uptake, storage, action, and metabolism of sex steroids. After menopause aromatization of androgens to estrogens in adipose tissue is one of the most important sources of estrogen in the circulation and for peripheral tissues. The aim of this study was to estimate local sex steroid concentrations in breast and abdominal subcutaneous (s.c.) adipose tissue, to compare them with plasma concentrations and to investigate possible correlations with body mass index (BMI). The patients were postmenopausal women undergoing surgery for non-oncological reasons (Group A; n = 35) and breast cancer patients (group B; n = 19). The concentrations of estrone, 17 beta-estradiol, estrone sulfate, 17 beta-estradiol sulfate, androstenedione, androstenediol (androst-5-ene-3 beta, 17 beta-diol), testosterone and dehydroepiandrosterone were measured. The method was based on frozen tissue homogenization, extraction with ethanol: acetone, delipidation, extraction of estrogens with ether, and of androgens with iso-octane in toluene, followed by RIA. The mean levels of steroids were higher in fat than in plasma, apart from testosterone. Levels of sulfates of estrogens and androstenediol were higher in breast than abdominal adipose tissue, and levels of estradiol lower. Positive correlations were found between BMI and tissue and plasma concentration of both estrone and androstenedione.
The purpose of these studies was to determine whether the antiobesity actions of dehydroepiandrosterone (DHEA) and DHEA-sulfate (DHEAS) observed in vivo are due to an influence on proliferation and/or differentiation in monolayer cultures of 3T3-L1 preadipocytes. For the proliferation study (Exp. 1), cells were grown in plating medium containing DHEA at 0, 5, 25, 50, or 100 microM for 1-4 d. DHEAS was added at the 100 microM level only. For the differentiation study (Exp. 2), cultures were grown in plating medium containing DHEA at 0, 5, 30, 60, 120, or 240 microM for 2-6 d. DHEAS was added at the 240 microM level only. In Exp. 3, the effect of DHEA on mature adipocytes was determined by exposing adipocytes grown in plating medium to DHEA at 0, 75, 125, and 250 microM for 1-4 d. In Exp. 1, preadipocyte proliferation decreased as the level of DHEA increased in cultures of 3T3-L1 cells. DHEAS had no effect on preadipocyte proliferation. The antiproliferative effect of DHEA was partially reversed by the addition of 1 microM mevalonic acid to proliferating cultures containing 25 microM DHEA. In Exp. 2, preadipocyte differentiation decreased as the level of DHEA in the cultures increased. In contrast, neither DHEAS nor mevalonic acid treatment influenced preadipocyte differentiation decreased as the level and duration of DHEA treatment increased in cultures of mature adipocytes. These data support the hypothesis that DHEA, but not DHEAS, is the active form of the steroid that attenuates obesity via altering preadipocyte proliferation and differentiation. The addition of 1 microM mevalonic acid to cultures of 3T3-L1 preadipocytes partially reversed DHEA's antiproliferative effects.
The purpose of this study was to determine if the antiobesity actions of dehydroepiandrosterone (DHEA) observed in vivo are due to an influence on the proliferation and differentiation of primary cultures of stromal-vascular (SV) cells isolated from human adipose tissue.
SV cells were isolated from subcutaneous adipose tissue obtained from a young adult female undergoing elective liposuction. For the proliferation assay (Experiment 1), cultures were fed proliferation media containing 0, 5, 25 or 100 microM DHEA for 3d. At the end of this treatment period, cultures were either prepared for counting or for determining their metabolic activity using the Alamar Blue staining procedure. For the differentiation assays (Experiment 2), cultures were fed differentiation media containing 0, 25 or 50 microM DHEA for 20 d. At the end of this treatment period, cultures were either prepared for lipid staining using Oil Red O or for marker enzyme analysis (glycerol-3-phosphate dehydrogenase activity; GPDH). To determine if the stimulatory effects of DHEA on SV cell differentiation were dependent on the presence of thiazolidinediones (Experiment 3), cultures of differentiating SV cells were incubated in the presence and absence of BRL 49653 and either 0, 25 or 50 microM DHEA.
In Experiment 1, cultures treated with 25 and 100 microM DHEA had fewer cells than cultures treated with either 0 or 5 microM DHEA. Alamar Blue staining decreased as the level of DHEA in the cultures increased. In Experiment 2, cultures treated with DHEA had more lipid and GPDH activity than control cultures. In Experiment 3, cultures treated with BRL 49653 had more triglyceride than cultures treated without BRL 49653. Likewise, cultures treated with DHEA had more triglyceride than their non-DHEA controls. Regardless of the BRL status, cultures supplemented with DHEA had more triglyceride than control cultures.
These data suggest that in cultures of SV cells from human adipose tissue, DHEA supplementation attenuates proliferation and enhances differentiation. These data support the hypothesis that DHEA directly attenuates preadipocyte proliferation in humans as we previously demonstrated in primary cultures of pig and rat SV cells and in cultures of 3T3-L1 preadipocytes. In contrast, DHEA stimulated the differentiation of human preadipocytes, which is contrary to its actions in differentiating cultures of preadipocytes from animals.
Adipogenesis contributes to the pathogenesis of thyroid eye disease (TED). Thyrotropin receptor (TSHR) transcripts are present in orbital fat. This study was conducted to determine whether they are expressed as functional protein, and if so, whether this is restricted to TED orbits or to a particular stage in adipocyte differentiation.
Samples of fat were obtained from 18 TED-affected orbits and 4 normal orbits, and 9 were obtained from nonorbital locations. Frozen sections were examined by immunocytochemistry using monoclonal antibodies specific for the human TSHR. Samples were disaggregated and the preadipocytes separated from the mature by differential centrifugation and cultured in serum-free or DM and examined for morphologic changes, oil red O and TSHR staining, and TSH-induced cyclic adenosine monophosphate (cAMP) production.
Marked immunoreactivity was observed in frozen sections from all three TED samples and faint staining in both normal orbital fat samples. In vitro, 1% to 5% of preadipocytes displayed TSHR immunoreactivity in five of six TED and two of three normal orbital samples and in three of five nonorbital samples. Differentiation, was induced in all 14 orbital samples. Three of four nonorbital samples contained occasional differentiated cells. Fifty percent to 70% of differentiating cells demonstrated receptor immunoreactivity. Two of three TED and four of four nonorbital preadipocytes in DM and/or mature adipocytes displayed a TSH-mediated increase in cAMP.
The results indicate that orbital fat TSHR transcripts are expressed as protein, which can be functional. This is not aberrant in TED orbits, although expression may be upregulated. The majority of preadipocytes undergoing differentiation express the receptor, indicating a key role for this population in one mechanism for increasing orbital volume.
Background:
Four retrospective studies have reported premature mortality in patients with hypopituitarism with standard mortality ratios (SMRs) varying between 1.20 and 2.17. Patients with hypopituitarism have complex endocrine deficiencies, and the mechanisms underpinning any excess mortality are unknown. Furthermore, the suggestion has emerged that endogenous growth-hormone deficiency might account for any excess mortality. We aimed to clarify these issues by doing a large prospective study of total and specific-cause mortality in patients with hypopituitarism.
Methods:
We followed up 1014 UK patients (514 men, 500 women) with hypopituitarism from January, 1992, to January, 2000. 573 (57%) patients had non-functioning adenomas, 118 (12%) craniopharyngiomas, and 93 (9%) prolactinomas. SMRs were calculated as the ratio of observed deaths to the number of deaths in an age-matched and sex-matched UK population.
Findings:
The number of observed deaths was 181 compared with the 96.7 expected (SMR 1.87 [99% CI 1.62-2.16], p<0.0001). Univariate analysis indicated that mortality was higher in women (2.29 [1.86-2.82]) than men (1.57 [1.28-1.93], p=0.002), in younger patients, in patients with an underlying diagnosis of craniopharyngioma (9.28 [5.84-14.75] vs 1.61 [1.30-1.99], p<0.0001), and in the 353 patients treated with radiotherapy (2.32 [1.71-3.14] vs 1.66 [1.30-2.13], p=0.004). Excess mortality was attributed to cardiovascular (1.82 [1.30-2.54], p<0.0001), respiratory (2.66 [1.72-4.11], p<0.0001), and cerebrovascular (2.44 [1.58-4.18], p<0.0001) causes. There was no effect of hormonal deficiency on mortality, except for gonadotropin deficiency, which, if untreated was associated with excess mortality (untreated 2.97 [2.13-4.13] vs treated 1.42 [0.97-2.07], p<0.0001). Multiple regression analyses identified age at diagnosis, sex, a diagnosis of craniopharyngioma, and untreated gonadotropin deficiency as independent significant factors affecting mortality.
Interpretation:
Patients with hypopituitarism have excess mortality, predominantly from vascular and respiratory disease. Age at diagnosis, female sex, and above all, craniopharyngioma were significant independent risk factors. Specific endocrine-axis deficiency, with the exception of untreated gonadotropin deficiency, does not seem to have a role.
Dehydroepiandrosterone sulfate levels have been inversely related with cardiovascular mortality in men, but findings have been inconsistent, and there are few data in women. We examined the relationship between baseline circulating dehydroepiandrosterone sulfate levels and subsequent all-cause and cardiovascular mortality in 963 men and 1171 women, 65-76 yr old, surveyed in 1991-1995, and followed up until August 2000 (when 296 deaths had occurred). All-cause and cardiovascular disease mortality rates were highest in the lowest dehydroepiandrosterone sulfate quartile in men; and thereafter, rates did not differ significantly in the upper three quartiles. This pattern remained after excluding those with previous history of cardiovascular disease and, in multivariate analyses, was independent of age, cigarette smoking habit, systolic blood pressure, body mass index, blood cholesterol, and steroid use. There was no significant association of dehydroepiandrosterone sulfate and mortality in women. The multivariate adjusted relative risks for all-cause mortality by sex-specific increasing quartile of dehydroepiandrosterone sulfate were 1.00, 0.66 (95% confidence interval, 0.44-1.01), 0.70 (0.46-1.07), 0.73 (0.48-1.10), respectively, for men and 1.00, 0.71 (95% confidence interval, 0.41-1.24), 0.97 (0.58-1.62), and 1.14 (0.69-1.88), respectively, for women. In older men and women, there is no consistent relationship between dehydroepiandrosterone sulfate and all-cause or cardiovascular mortality. The highest mortality rates were observed in the lowest quartile in men, but the highest rates were in the highest quartile in women.
Dehyroepiandrosterone (DHEA), an adrenal-derived steroid, has been clinically implicated in protection against coronary artery disease and experimentally in inhibition of atherosclerosis and plaque progression. Because DHEA is enzymatically metabolized to androgens or estrogens, it is not clear whether DHEA exerts effects directly or after conversion to these hormones, both of which are associated with well-characterized pathways of action. We therefore examined the effects of DHEA on proliferation of human vascular smooth muscle cells (VSMCs) in culture in the presence or absence of the ER antagonist ICI 182,780 and the AR antagonist flutamide and compared them with the effects of 17beta-estradiol, androstenedione, and T. We also determined the affinity of DHEA for ERs and ARs in VSMC and its specific binding in intact cells. To explore a possible mechanism for DHEA action in these cells, we measured the phosphorylation of ERK-1, c-jun N-terminal protein kinase, and p38 (three members of the MAPK superfamily). Both DHEA and 17beta-estradiol significantly inhibited platelet derived growth factor (PDGF)-BB-induced increases in VSMC proliferation, whereas androstenedione and T increased proliferation. Although E2-induced inhibition of the PDGF effect was abolished by ICI 182,780 and T-induced stimulation was abolished by flutamide, neither receptor antagonist altered the inhibitory effect of DHEA. Binding studies confirmed the presence of both ERs and ARs; DHEA showed minimal affinity for either receptor but bound specifically and with high affinity to putative receptors in intact cells. Following 4-h incubation with DHEA (1-100 nM), ERK1 phosphorylation was significantly reduced in a dose-dependent manner, whereas neither c-jun N-terminal protein kinase nor p38 kinase activity was altered by either PDGF-BB or DHEA. DHEA inhibits human VSMC proliferation by a mechanism independent of either ARs or ERs, presumably via a DHEA-specific receptor that involves ERK1 signaling pathways.
A male type-2 diabetic, treated with the peroxisome proliferator-activated receptor (PPAR) agonist, Pioglitazone, experienced exacerbation of his thyroid eye disease (TED), which had been stable and inactive for more then 2 yr. Expansion of the orbital fat developed, and we have investigated the effects of PPAR gamma agonists, including Pioglitazone and, subsequently, an antagonist on the adipogenesis of preadipocytes from TED orbits and Graves' neck fats. The percentage of differentiating cells, assessed by oil red O staining, morphological changes, and PPAR gamma transcript levels, was determined for preadipocytes in hormone/agonist-induced models of adipogenesis, supplemented or not with PPAR gamma agonists or antagonist. The PPAR gamma agonists resulted in a 2- to 13-fold increase, and a PPAR gamma antagonist produced a 2- to 7-fold reduction in adipogenesis in vitro. Effects were dose dependent and maximal at 1 or 10 micro M. We suggest that care should be exercised when selecting patients for treatment with PPAR gamma agonists and that such agonists may be contraindicated in individuals with a previous history of autoimmune thyroid or eye diseases. Our work also suggests that PPAR gamma antagonists could provide a novel therapy for TED patients in the active stage of disease.
We found that UCP-1 and UCP-3 mRNA expression levels and the UCP-1 protein content in brown adipose tissue (BAT) were reduced in prediabetic OLETF rats than the lean LETO rats. Administration of dehydroepiandrosterone (DHEA) for 17 days induced remarkable weight loss, which was in part attributed to an enhanced utilization of ingested energy. DHEA administration significantly increased the levels of BAT UCP-1 and UCP-3 mRNA expression. Among the upstream signals for UCP-1 regulation, expression levels of the beta 3 adrenergic receptor (beta(3)AR) and PPAR gamma coactivator-1 (PGC-1) were significantly decreased in the OLETF rats and increased by DHEA administration. The decreased expression levels of UCP-1 and its upstream regulators, beta(3)AR and PGC-1, in BAT may contribute to inefficient energy utilization and obesity in OLETF rats, which was corrected by DHEA treatment.
Patients who received pituitary-derived growth hormone (GH) are at excess risk of mortality from Creutzfeldt-Jakob disease. We investigated whether they were at increased risk of death from other conditions, particularly preventable conditions.
A cohort (N=6107) from known US pituitary-derived GH recipients (treated 1963-1985) was studied. Deaths were identified by reports from physicians and parents and the National Death Index. Rates were compared with the expected rates for the US population standardized for race, age, and sex.
There were 433 deaths versus 114 expected (relative risk [RR], 3.8; 95% confidence interval [CI], 3.4-4.2; P<.0001) from 1963 through 1996. Risk was increased in subjects with GH deficiency caused by any tumor (RR, 10.4; 95% CI, 9.1-12.0; P<.0001). Surprisingly, subjects with hypoglycemia treated within the first 6 months of life were at extremely high risk (RR, 18.3; 95% CI, 9.2-32.8; P<.0001), as were all subjects with adrenal insufficiency (RR, 7.1; 95% CI, 6.2-8.2; P<.0001). A quarter of all deaths were sudden and unexpected. Of the 26 cases of Creutzfeldt-Jakob disease, four cases have died since 2000.
The death rate in pituitary-derived GH recipients was almost four times the expected rate. Replacing pituitary-derived GH with recombinant GH has eliminated only the risk of Creutzfeldt-Jakob disease. Hypoglycemia and adrenal insufficiency accounted for far more mortality than Creutzfeldt-Jakob disease. The large number of potentially preventable deaths in patients with adrenal insufficiency and hypoglycemia underscores the importance of early intervention when infection occurs in patients with adrenal insufficiency, and aggressive treatment of panhypopituitarism.
Dehydroepiandrosterone (DHEA), the most abundant steroid hormone in human blood, is considered to be one of fat-reducing hormones. However, the molecular mechanisms underlying DHEA mode of action in obesity has not been fully clarified. The pivotal role in the maintenance of cellular lipid and energy balance is played by peroxisome proliferator-activated receptor alpha (PPARalpha) which acts as transcriptional activator of numerous genes encoding enzymes involved in fatty acid catabolism. Lately published papers suggest that resistin, a low molecular-weight protein produced by adipose tissue, may act as an inhibitor of adipocyte differentiation and could regulate adipose tissue mass. Recent studies have established that the promoter region of the resistin gene contains several putative PPAR response elements. Since DHEA has been characterized as a peroxisome proliferator able to induce hepatic genes through PPARalpha, we hypothesised that DHEA might affect PPARalpha and, subsequently, resistin gene expression in adipose tissue. In order to test this hypothesis, an experiment was performed comparing PPARalpha and resistin gene expression in white adipose tissue (WAT) of male Wistar rats fed standard or DHEA-supplemented (0.6% (w/w)) diet for 2 weeks. DHEA administration to the rats induced PPARalpha and resistin gene expression in WAT (3- and 2.25-fold, respectively; as determined by real-time reverse transcription-polymerase chain reaction (RT-PCR)); reduced body weight, epididymal adipose tissue mass and decreased serum leptin levels. We propose that DHEA may impact on the transcription of resistin gene through a mechanism involving PPARalpha and that an elevated resistin level may lead to an inhibition of adipogenesis and a decrease in adipose tissue mass.
Dehydroepiandrosterone (DHEA), a steroid hormone, modified the proliferation of human umbilical vein endothelial cells in a dose-dependent manner. Its inactive sulfate ester (DHEA-S) and two of its metabolites -- estradiol and testosterone -- had no inhibitory effect at physiological concentrations. Antiproliferation was associated with arrest in the G1 phase of the cell cycle, but not with cell death, as evaluated by cleavage of poly(ADP-ribose) polymerase and exposure of phosphatidylserine. The effect was not blocked by inhibitors of androgen or estrogen receptors. DHEA diminished the levels of phosphorylated retinoblastoma protein and increased the expression of p53 and p21 mRNAs. These results show that DHEA inhibits endothelial cell proliferation by regulating cell cycle relevant proteins through a cytoplasmic steroid hormone-independent pathway.
Dehydroepiandrosterone (DHEA), an adrenal steroid, is known to decrease body fat. Thus, it may also alter the endocrine functions of adipose tissue. The aim of this study was to determine if administration of DHEA might influence adiponectin gene expression and secretion from adipose tissue. We demonstrate here the inducing effect of exogenously administered DHEA on adiponectin gene expression in epididymal WAT and adiponectin levels in serum of rats fed a DHEA-containing diet (0.6%, w/w) for 2 weeks, accompanied by a reduction in epididymal adipose tissue mass. A corresponding increase in peroxisome proliferator-activated receptor gamma (PPAR(gamma)) mRNA expression suggests that PPAR(gamma) may be involved in the up-regulation of adiponectin gene expression after DHEA treatment. The presented observations indicate that the positive effects of DHEA, which seems to play a protective role against insulin resistance and atherosclerosis, may be in fact indirect and due to up-regulation of adiponectin gene expression and stimulation of adiponectin secretion from adipose tissue.
We examined plasma and fat tissue sex steroid levels in a sample of 28 men aged 24.8-62.2 years (average BMI value of 46.3 +/- 12.7 kg/m(2)). Abdominal adipose tissue biopsies were obtained during general or obesity surgery. Omental and subcutaneous adipose tissue steroid levels were measured by gas chromatography and chemical ionization mass spectrometry after appropriate extraction procedures. BMI and waist circumference were negatively correlated with plasma testosterone (r = -0.49 and -0.50, respectively, p < 0.01) and dihydrotestosterone (r = -0.58 and -0.56, respectively, p < 0.01), and positively associated with estrone levels (r = 0.64 and 0.62, respectively, p < 0.001). Regional differences in adipose tissue steroid levels were observed for dihydrotestosterone (p < 0.005), androstenedione (p < 0.0001) and dehydroepiandrosterone levels (p < 0.05), which were all significantly more concentrated in omental versus subcutaneous fat. Positive significant associations were found between circulating level of a steroid and its concentration in omental and subcutaneous adipose tissue, for estrone (r = 0.72 and 0.57, respectively, p < 0.01), testosterone (r = 0.66 and 0.58, respectively, p < 0.01) and dihydrotestosterone (r = 0.58 and 0.45, respectively, p < 0.05). Positive correlations were observed between plasma dehydroepiandrosterone-sulfate and omental (r = 0.56, p < 0.01) as well as subcutaneous adipose tissue dehydroepiandrosterone level (r = 0.38, p = 0.05). Positive significant associations were found between omental adipocyte responsiveness to positive lipolytic stimuli (isoproterenol, dibutyryl cyclic AMP and forskolin) and plasma or omental fat tissue androgen levels. In conclusion, although plasma androgen or estrogen levels are strong correlates of adipose tissue steroid content both in the omental and subcutaneous fat depots, regional differences may be observed. Androgen concentration differences in omental versus subcutaneous adipose tissue suggest a depot-specific impact of these hormones on adipocyte function and metabolism.
The aim of this study was to investigate whether DHEA alters the proliferation and differentiation of human sc and visceral adipose cells in primary cultures.
Sc and omental adipose tissue was obtained from 10 female donors aged 36+/-3.6 yr with a body mass index (BMI) of 33+/-3.21 kg/m2. Stromal vascular cells were isolated and cultured using modified procedures described by Entenmann and Hauner. For the proliferation assay, stromal-vascular cells from sc and visceral adipose tissue cultures were fed with proliferation media containing 0, 25 or 100 microM DHEA for 3 days. At the end of this treatment period, two type cultures were prepared for determining their metabolic activity using the sulforhodamine B staining procedure.
The metabolic activity of proliferating human visceral adipose tissue was higher than sc adipose tissue. The activity of proliferating human visceral tissue cultures decreased more than the sc tissue as the level of DHEA in the cultures was increased.
These data suggest that DHEA predominantly influences the proliferation and differentiation of human omental adipose tissue.
The survival rate of patients with primary adrenal insufficiency (Addison's disease) undergoing currently accepted replacement therapy is not known, although well-informed patients are considered to have a normal survival rate. In this study, we evaluated the mortality of patients with Addison's disease in Sweden.
A population-based, retrospective, observational study was performed, using the National Swedish Hospital and Cause of Death Registers, covering the period from 1987-2001. After a diagnosis of Addison's disease, each patient was followed until the end of follow-up or death. Mortality was compared with that of the Swedish background population.
We identified 1675 patients (995 women and 680 men) diagnosed with primary adrenal insufficiency. The average follow-up from initial diagnosis was 6.5 yr. Five hundred seven patients died during the study period compared with an expected 199. The risk ratio for all-cause mortality was 2.19 (confidence interval 1.91-2.51) for men and 2.86 (confidence interval 2.54-3.20) for women. The excess mortality in both men and women was attributed to cardiovascular, malignant, and infectious diseases. Concomitant diabetes mellitus was observed in 12% of the patients, but only contributed to the increased mortality to a minor extent.
Compared with the background population, we observed that the risk ratio for death was more than 2-fold higher in patients with Addison's disease. Cardiovascular, malignant, and infectious diseases were responsible for the higher mortality rate.
PPAR␥ in thyroid eye disease, contra-indication for thiazolidenedione use?
- K Starkey
- A Heufelder
- G Baker
- W Joba
- M Evans
- S Davies
- M Ludgate
Starkey, K., Heufelder, A., Baker, G., Joba, W., Evans, M., Davies, S., Ludgate, M., 2003.
PPAR␥ in thyroid eye disease, contra-indication for thiazolidenedione use? J.
Clin. Endocrinol. Metab. 88, 55-59.
Adrenal Androgens in Clinical Medicine
- L Parker
Parker, L., 1989. Adrenal Androgens in Clinical Medicine. Academic Press, Inc., San
Diego.
Relationship of dehydroepiandrosterone sulfate in the elderly with functional, psychological and mental status and short term mortality: a French community-based study
- C Berr
- S Lafont
- B Deburie
- J Dartigues
- E Baulieu
Berr, C., Lafont, S., Deburie, B., Dartigues, J., Baulieu, E., 1996. Relationship of dehydroepiandrosterone sulfate in the elderly with functional, psychological and
mental status and short term mortality: a French community-based study. Proc.
Natl. Acad. Sci. U.S.A. 93, 13410-13415.