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Levels of basal T secretion in vitro after cortical lesions. * = significant difference in comparison with intact rats; # = significant difference in comparison with rats underwent sham occipital cortical lesion. Data are expressed as mean ?SEM, p< 0.05.
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In addition to being regulated by the hypothalamo-hypophyseal system, testosterone (T) secretion is influenced by a number of less understood mechanisms. The aim of the present study was to examine whether defined areas of the right cerebral cortex could modulate T production.
In adult male Wistar rats right frontal or occipital decortication, ante...
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Context 1
... cortical ablation resulted in a significant rise in basal T secretion in vitro (p< 0.05). By contrast, frontal cortical lesion did not interfere with this parameter (Figure 3). Posterior callosotomy induced a significant increase in T release (p< 0.05), while anterior transection of the corpus callosum did not determine any significant effect (Figure 4). ...
Citations
... It is a possibility that other significant correlations would result from a larger sample size. However, it is worth noticing that the occipital lobe has been associated with inhibitory control of TS secretion from gonads via a pituitary independent mechanism (Lepore et al., 2006(Lepore et al., , 2008, thus suggesting that parts of the occipital lobe is part of the direct neural fine-tuning mechanism involved in production of male TS. ...
Per- and polyfluoroalkyl substances (PFASs) are emerging in the Arctic and accumulate in brain tissues of East Greenland (EG) polar bears. In vitro studies have shown that PFASs might possess endocrine disrupting abilities and therefore the present study was conducted to investigate potential PFAS induced alterations in brain steroid concentrations. The concentrations of eleven steroid hormones were determined in eight brain regions from ten EG polar bears. Pregnenolone (PRE), the dominant progestagen, was found in mean concentrations of 5–47 ng/g (ww) depending on brain region. PRE showed significantly (p
... Thus, it is possible that a pCA induced decrease in serotonin concentration in the testis provokes vascular changes in the gonad and affects the availability of FSH, LH and nutrients for steroidogenesis, differentiation of germinal cells and spermatogenesis. Another possibility is that decreases in serum testosterone concentration induced by the administration of pCA are related to modification of neural information received by the testis, which appears to exert fine control on their function193194195196197198199. At the present, there is no anatomic evidence of direct neural communication between the DRN and MRN nuclei and the testis. ...
Serotonin, a biogenic amine, is present in significant amounts in many structures of the CNS. It is involved in regulation of a wide variety of physiological functions, such as sensory and motor functions, memory, mood, and secretion of hormones including reproductive hormones. It has also been implicated in the etiology of a range of psychiatric disorders such as anxiety, depression, and eating disorders, along with other conditions such as obesity and migraine. While some drugs that affect serotonin, such as fenfluramine and fluoxetine, have been successfully used in treatment of a range of psychiatric diseases, others, such as the amphetamine analogues MDMA and METH, are potent psychostimulant drugs of abuse. Alterations in serotonergic neurons caused by many of these drugs are well characterized; however, little is known about the reproductive consequences of such alterations. This review evaluates the effects of drugs such as MDMA, pCA, fenfluramine, and fluoxetine on serotonergic transmission in the brain, examines the relationships of these drug effects with the neuroendocrine mechanisms modulating reproductive events such as gonadotropin secretion, ovulation, spermatogenesis, and sexual behavior in animal models, and discusses possible reproductive implications of these drugs in humans.
... There is growing evidence that brain areas, such as the caudal raphe nuclei, locus coeruleus, periaqueductal grey matter, are transneuronally connected with the gonads (Gerendai et al., 2000a;Gerendai et al., 2000b) and their involvement in a complementary control mechanism independent of the pituitary gland has been suggested. The role of this neural influence in the control of gonadal functions is consistently shown by studies based on transections or lesions in the peripheral or central nervous system (Gerendai et al., 1997;Banczerowski et al., 2001) and by recent observations showing an inhibitory effect of the right occipital cortex on tes-ticular steroidogenesis (Lepore et al., 2006). Furthermore, it has been recently demonstrated that the complete transection of the corpus callosum leads to an increase in T secretion of hemigonadectomized rats (Banczerowski et al., 2000), suggesting that the callosotomy-induced upregulation of testicular steroidogenesis is pituitary-independent. ...
... Rats from groups I, II and III were killed seven days post-surgery and those from groups IV seven days after the last intervention. For groups II and III, serum T and LH levels were determined by radioimmunoassay (RIA) as previously described in detail (Lepore et al., 2006). To perform posterior callosotomy, rats were anesthetized with zolazepam and tiletamine (Zoletil, Virbac, 50 mg/kg) and placed on a stereotaxic frame with the head in a 3.3 mm dorsoventral nose-down position relative to the interauricular line (Paxinos and Watson, 1997). ...
... In conclusion, our results suggest that in the right occipital cortical areas Oc1 and Oc2 AR expression can be significantly influenced by the contralateral areas independently from the pituitary gland since LH serum levels did not change in either sham callosotomized or callosotomized rats. This is consistent with a previous study showing that right occipital decortication and posterior callosotomy resulted in changes in gonadal T production in vitro without any significant variation on serum T and LH levels (Lepore et al., 2006). All these data are in accordance with other reports describing pure neural links between the nervous system and the gonads (Gerendai et al., 1986;Lee et al., 2002;Selvage et al., 2006). ...
Gonadal steroidogenesis can be influenced by direct neural links between the central nervous system and the gonads. It is known that androgen receptor (AR) is expressed in many areas of the rat brain involved in neuroendocrine control of reproduction,such as the cerebral cortex.It has been recently shown that the occipital cortex exerts an inhibitory effect on testicular stereoidogenesis by a pituitary-independent neural mechanism. Moreover, the complete transection of the corpus callosum leads to an increase in testosterone (T) secretion of hemigonadectomized rats. The present study was undertaken to analyze the possible corticocortical influences regulating male reproductive activities. Adult male Wistar rats were divided into 4 groups: 1) intact animals as control; 2) rats undergoing sham callosotomy; 3) posterior callosotomy; 4) gonadectomy and posterior callosotomy. Western blot analysis showed no remarkable variations in cortical AR expression in any of the groups except in group I where a significant decrease in AR levels was found. Similarly, both immunocytochemical study and cell count estimation showed a lower AR immunoreactivity in occipital cortex of callosotomized rats than in other groups. In addition, there was no difference in serum T and LH concentration between sham-callosotomized and callosotomized rats. In conclusion, our results showthat posterior callosotomy led to a reduction in AR in the right occipital cortex suggesting a putative inhibiting effect of the contralateral cortical area.
