Mary Gannon

University of Minnesota Twin Cities | UMN · Department of Food Science & Nutrition and Department of Medicine, Division of Endocrinology and Diabetes

Background: Current mathematical models of postprandial glucose metabolism in people with normal and impaired glucose tolerance rely on insulin measurements and are therefore not applicable in clinical practice. This research aims to develop a model that only requires glucose data for parameter estimation while also providing useful information on...

Background and objective The oral minimal model of glucose dynamics is one of the most prominent methods for assessing postprandial glucose metabolism. The model yields estimates of insulin sensitivity and the meal-related appearance of glucose from insulin and glucose data after an oral glucose challenge. Despite its success, the oral minimal mode...

Objective: We have been interested in determining the effects of dietary changes on fuel metabolism and regulation in men with type 2 diabetes mellitus (T2DM). In this study, the changes in 24-hr circulating lipid profiles were determined when the major fuel source was endogenous versus exogenous fat. Methods: Seven males with T2DM were randomiz...

Background: We recently have reported the 24-hour glucose, insulin and glucagon responses to a 72-hour fast compared to a 72-hour macronutrient-sufficient, carbohydrate-free diet in men with type 2 diabetes. The 72-hour time period was used because it is the time required for the major metabolic adjustments to a lack of food to be instituted. As p...

A large number of medications have been implicated in the genesis of gynecomastia. However, gynecomastia is common in men, asymptomatic, increases with age, and is considered to be due to an increased estradiol/testosterone ratio. This complicates the interpretation of medication-related gynecomastia. Therefore, we have reviewed the literature in o...

The majority of individual amino acids increase insulin and attenuate the plasma glucose response when ingested with glucose. Objective. To determine whether ingestion of two amino acids simultaneously, with glucose, would result in an additive effect. Leucine (Leu) and glycine (Gly) were chosen because they were two of the most potent glucose-lowe...

Leucine (Leu) is well recognized to stimulate insulin secretion and to reduce the glucose rise when ingested with glucose. Glycine (Gly) reduces the glucose rise, but only weakly stimulates insulin secretion. We have shown that both were particularly potent in their ability to attenuate the glucose response to 25 g glucose. The current study was de...

Most individual amino acids stimulate insulin secretion and attenuate the plasma glucose response when ingested with glucose. We determined whether ingestion of two amino acids simultaneously with glucose would result in an additive effect on the glucose area response compared with ingestion of amino acids individually. Leucine and phenylalanine we...

Body proteins are being synthesized and degraded continuously (1). The estimated turnover is ∼210 g/day (2). Amino acids resulting from protein degradation can be recycled (reused for synthesis), but this is incomplete. Therefore, dietary protein is necessary for maintenance of lean body mass. Also, dietary protein is required to replace protein lo...

We have shown that phenylalanine (Phe) or leucine (Leu), when ingested with glucose, reduced the glucose response. Leu increased, whereas Phe had little effect on the insulin response. We then were interested in whether the effects would be additive if Phe and Leu were ingested together with glucose. On 4 separate days, 8 healthy subjects were stud...

Objective: Dreamfields pasta is a modified commercially available pasta that is claimed to raise blood glucose much less than standard, unmodified pasta. Our objective was to quantify the blood glucose response to ingested Dreamfields pasta compared with an unmodified pasta. Research Design and Methods: Using a blinded, randomized, crossover design...

We previously reported that a weight-maintenance diet with a carbohydrate:protein:fat ratio of 30:30:40%, ingested for 5 weeks, improved blood glucose control in subjects with untreated type 2 diabetes. In this study we also determined that insulin and insulin-like growth factor-I (IGF-I) were increased. In this report we provide further informatio...

We have developed a diet that over 5 weeks dramatically lowers plasma glucose in people with type 2 diabetes mellitus. This diet consists of 30% carbohydrate, 30% protein, and 40% fat and is referred to as a Low Biologically Available Glucose (LoBAG) diet. The diet also resulted in an approximately 30% increase in fasting insulin-like growth factor...

OBJECTIVE: Dreamfields pasta is a modified commercially available pasta that is claimed to raise blood glucose much less than standard, unmodified pasta. Our objective was to quantify the blood glucose response to ingested Dreamfields pasta compared with an unmodified pasta. RESEARCH DESIGN AND METHODS: Using a blinded, randomized, crossover design...

Interest in the effect of proteins or amino acids on glucose metabolism dates back at least a century, largely because it was demonstrated that the amino acids from ingested protein could be converted into glucose. Indeed, these observations influenced the dietary information provided to people with diabetes. Subsequently it was shown that ingested...

We previously determined that a weight-maintenance, non-ketogenic diet containing 30% carbohydrate (CHO), 30% protein, 40% fat, (30:30:40) (LoBAG30) decreased glycated hemoglobin (%tGHb) from 10.8 to 9.1% over a 5 week period in subjects with untreated type 2 diabetes. Both the fasting glucose and postprandial glucose area were decreased. Our objec...

We are interested in the metabolic response to ingested macronutrients and the interaction between macronutrients in meals. Recently, we have determined the insulin and glucose response to ingestion of lard, olive oil, or safflower oil, fat sources varying in fatty acid composition and carbohydrate (CHO), in the form of potato. Our aim was to deter...

Ingested proteins are known to stimulate a rise in insulin and glucagon concentrations. In our effort to explain this effect, we have begun to measure the effect of individual amino acids. The objectives were to determine the effect of lysine ingestion on insulin and glucagon concentrations and whether the effect is moderated by glucose ingestion....

We are interested in the metabolic response to ingested macronutrients, and the interaction between macronutrients in meals. Previously, we and others reported that the postprandial rise in serum glucose following ingestion of 50 g carbohydrate, consumed as potato, was markedly attenuated when butter was ingested with the carbohydrate, whereas the...

Our laboratory is interested in the metabolic effects of ingested proteins. As part of this research, we currently are investigating the metabolic effects of ingested individual amino acids. The objective of the current study was to determine whether leucine stimulates insulin and/or glucagon secretion and whether, when it is ingested with glucose,...

We have been interested in the metabolic effects of ingested fuels, both in normal subjects and in people with type 2 diabetes. Recently, we have become interested in the regulation of glucose production and the regulation of gluconeogenesis in particular. We are not aware of a recent comprehensive review of these topics. Therefore, we have reviewe...

Objective The objective of the present study was to determine the degree to which ingested isoleucine modified the glucose, insulin and glucagon responses to ingested glucose. Design Nine healthy subjects were studied on 4 separate occasions. Plasma isoleucine, glucose, insulin, glucagon, and total alpha amino nitrogen were measured at various tim...

Diets with increased protein and reduced carbohydrates have been shown to improve body composition, lipid and lipoprotein profiles, and glycemic regulations associated with treatment of obesity and weight loss. Derived from these outcomes, high-protein, low-carbohydrate diets are also being examined for treatment of heart disease, metabolic syndrom...

In subjects with untreated type 2 diabetes, we previously determined that a weight-maintenance, non-ketogenic diet containing 30 % protein, 50 % fat and 20 % carbohydrate (30:50:20) decreased the percentage total glycohaemoglobin (%tGHb) by 2.2 % glycohaemoglobin over 5 weeks compared to a diet recommended for the American public (protein-fat-carbo...

We recently reported that in subjects with untreated type 2 diabetes a 5-wk diet of 30:30:40 carbohydrate/protein/fat ratio resulted in a significant decrease in 24-h integrated glucose, total %glycohemoglobin, and total cholesterol compared with a control diet of 55:15:30 carbohydrate/protein/fat given at the beginning of the 5-wk period. Body wei...

As part of our studies of the metabolic effects of ingested proteins, we are currently investigating the effects of ingestion of individual amino acids. The objective of the present study was to determine whether ingested phenylalanine stimulates insulin and/or glucagon secretion, and if phenylalanine ingested with glucose modifies the insulin, glu...

There is a concern that an "epidemic of obesity" is occurring in Western societies. One consequence of obesity is that type 2 diabetes may develop. Presumably, a great increase in body weight would continue in people with diabetes and may be accelerated due to pharmacological treatment. In this retrospective study, we tested the hypothesis that the...

We recently reported that in subjects with untreated type 2 diabetes mellitus, a 5-week diet of 20:30:50 carbohydrate-protein-fat ratio resulted in a dramatic decrease in 24-hour integrated glucose and total glycohemoglobin compared with a control diet of 55:15:30. Body weight, total cholesterol, low-density lipoprotein cholesterol, high-density li...

Over the past several years our research group has taken a systematic, comprehensive approach to determining the effects on body function (hormonal and non-hormonal) of varying the amounts and types of proteins, carbohydrates and fats in the diet. We have been particularly interested in the dietary management of type 2 diabetes. Our objective has b...

Since glycohemoglobin values are widely used clinically as a surrogate for average glucose concentration over an extended period of time, we decided to determine the actual relationship between 24-hour integrated glucose values and percent total glycohemoglobin (%tGHb) in cohorts of people with and without diabetes. In 48 people without known diabe...

Phosphorylase is regulated by a number of small-molecular-weight effectors that bind to three sites on the enzyme. Recently, a fourth site referred to as the indole-inhibitor site has been identified. Synthetic compounds bind to the site and inhibit activity. However, the effects of these compounds in the presence of other endogenous effectors are...

We previously have shown that an affinity, high-performance liquid chromatography (HPLC) method is a highly reproducible and sensitive method for determining percent total glycohemoglobin (tGHb) in people with diabetes. In this study we extended the use of this method to a determination of the correlation of percent tGHb with the fasting plasma glu...

There has been interest in the effect of various types and amounts of dietary carbohydrates and proteins on blood glucose. On the basis of our previous data, we designed a high-protein/low-carbohydrate, weight-maintaining, nonketogenic diet. Its effect on glucose control in people with untreated type 2 diabetes was determined. We refer to this as a...

Ingested protein results in an increase in circulating insulin and glucagon concentrations and no change, or a slight decrease, in circulating glucose. In subjects with type 2 diabetes, when protein is ingested with glucose, insulin is further increased and the glucose rise is less than when glucose is ingested alone. Presumably these effects are d...

Background One of the major interests in our laboratory has been to develop a scientific framework for dietary advice for patients with diabetes. Knowledge regarding the metabolic consequences and potential effects on health of protein in people with type 2 diabetes has been a particular interest. Results We recently have completed a study in whic...

In single-meal studies, dietary protein does not result in an increase in glucose concentrations in persons with or without type 2 diabetes, even though the resulting amino acids can be used for gluconeogenesis. The metabolic effects of a high-protein diet were compared with those of the prototypical healthy (control) diet, which is currently recom...

In a randomized, crossover 5-wk study design, we recently reported that a weight-maintaining diet in which the percentage of total food energy as protein was increased from 15-30% resulted in a decrease in postprandial glucose and glycohemoglobin in people with untreated type 2 diabetes without a significant change in insulin. Protein was substitut...

Viscous dietary fibers can modify the alimentary responses to a meal and improve glucose tolerance. There may be a relationship between the effect of these fibers in the gut and the ability of the hormone cholecystokinin (CCK) to slow gastric emptying and affect glucose homeostasis. We investigated the acute and long-term (adaptive) glucose and CCK...

The metabolic effects of dietary protein are complex. In persons with type 2 diabetes, protein ingestion results in little or no increase in plasma glucose concentrations but a stimulation of insulin and glucagon secretion. Furthermore, when protein is ingested with glucose, a synergistic effect on insulin secretion is observed. The most potent pro...

Ingested protein increases circulating insulin concentrations. Several years ago it was also determined that an intravenously administered mixture of 10 essential amino acids stimulated insulin secretion. Of these, arginine was the most potent. The effect was synergistic with administered glucose. Because the amounts of amino acid administered intr...

We previously have reported that protein, on a weight basis, is just as potent as glucose in increasing the insulin concentration in people with type 2 diabetes. In people without diabetes, protein is only approximately 30% as potent as glucose in this regard. In the present study, we tested the hypothesis that the increased insulin responsiveness...

Hepatic glucose production is increased in people with type 2 diabetes. Glucose released from storage in liver glycogen by phosphorylase accounts for approximately 50% of the glucose produced after an overnight fast. Therefore, understanding how glycogenolysis in the liver is regulated is of great importance. Toward this goal, we have determined th...

Repetitive myocardial ischemia increases glucose uptake, but the effect on glycogen is unclear. Thirteen swine instrumented with a hydraulic occluder on the circumflex (Cx) artery underwent 10-min occlusions twice per day for 4 days. After 24 h postfinal ischemia and in the fasted state, echocardiogram and positron emission tomography imaging for b...

Amino acids derived from ingested protein are potential substrates for gluconeogenesis. However, several laboratories have reported that protein ingestion does not result in an increase in the circulating glucose concentration in people with or without type 2 diabetes. The reason for this has remained unclear. In people without diabetes it seems to...

We have reported that glycogen synthesis and degradation can occur in vivo without a significant change in the amount of phosphorylase a present. These data suggest the presence of a regulatable mechanism for inhibiting phosphorylase a activity in vivo. Several effectors have been described. AMP stimulates, whereas ADP, ATP, and glucose inhibit act...

Galactose is one of the monosaccharides of importance in human nutrition. It is converted to glucose-1-phosphate in the liver and subsequently stored as glycogen, or is converted to glucose and released into the circulation. The increase in plasma glucose is known to be modest following galactose ingestion. Whether this is due to a small increase i...

Ingested fructose is rapidly utilized by the liver and is either stored as glycogen, converted to glucose, or oxidized to CO2 for energy. The glycemic response to fructose is known to be modest. However, the relative importance of these pathways in humans is unclear. In the present study, a tritiated glucose tracer dilution technique was used to de...

The monosaccharides resulting from the digestion of ingested carbohydrates are glucose, fructose, and galactose. Of these three monosaccharides, only ingested glucose resulted in a large increase in the plasma glucose concentration. Fructose (Metabolism 41:510-517, 1992) and galactose (Metabolism 42:1560-1567, 1993) had only a minor effect. Therefo...

The glycogen concentration in liver is altered in various pathophysiologic states. In fasted rats, it is higher in diabetic, and lower in adrenalectomized rats compared to control animals. In fed rats, it is lower in diabetic, and little changed in adrenalectomized animals compared to controls. We were interested in determining whether the activity...

Discrete-time state-space models were developed to describe contemporaneous responses of plasma insulin and glucose of normal human subjects. Male and female subjects ingested three consecutive identical meals from isocaloric diets classified as high-carbohydrate, high-fat, high-protein, or standard. Distinctly different glucose and insulin respons...

Glycogen storage disease type 0 (GSD-0) is a rare form of fasting hypoglycemia presenting in infancy or early childhood and accompanied by high blood ketones and low alanine and lactate concentrations. Although feeding relieves symptoms, it often results in postprandial hyperglycemia and hyperlactatemia. The glycogen synthase (GS) activity has been...

Ingested protein provides substrate for gluconeogenesis and strongly stimulates insulin and glucagon secretion, but it has little effect on the glucose concentration in people with type 2 diabetes. Ingested fructose also is a substrate for gluconeogenesis, modestly stimulates insulin and glucagon secretion, and has little effect on the plasma gluco...

Hepatic glycogen synthase activity is increased in diabetic animals. However, the relationship between enzymic activity, enzyme protein mass, and mRNA abundance has not been well characterized. In the present study, these relationships were determined in 3- and 8-day diabetic, fed and fasted rats. The results were compared to data obtained in norma...

Noninsulin-dependent diabetes mellitus (NIDDM)* is a heterogenous disease that is genetically determined and, in most people, is dependent on aging and/or obesity for its expression. It is characterized frequently by a resistance to the metabolic effects of insulin (1,2) and always by a relatively impaired insulin secretory response to a high ambie...

Phosphorylase removes glucosyl units from the terminal branches of glycogen through phosphorolysis, forming glucose-1-P. It is present in two interconvertible forms, phosphorylase a and b. The a form is the active form and is rate limiting in glycogen degradation. The activities of phosphorylase a and of total phosphorylase as conventionally measur...

Adherence to a low-calorie diet often results in a decrease in blood glucose concentration in persons with non-insulin-dependent diabetes mellitus (NIDDM). Whether this is due to the resultant weight loss or to a decrease in caloric intake has been uncertain. We have obtained data previously that indicated a very short-term reduction in caloric int...

It generally is agreed that initiation of a glycogen molecule occurs through the addition of a linear array of glucose molecules to a protein referred to as glycogenin. The addition of glucosyl units is catalyzed by glycogenin itself. The product is then branched and expanded by other enzymes. This process has been studied best in skeletal muscle....

Rats fed ad libitum were given insulin alone (4 U/kg), glucagon alone (25 micrograms/kg), or insulin and glucagon sequentially. Phosphorylase a and synthase R activities, hepatic glycogen, uridine diphosphoglucose, inorganic phosphate (Pi), and plasma glucose, lactate, glucagon, and insulin concentrations were determined over the subsequent 40 min....

In a previous study, administration of casein hydrolysate to food-deprived rats at a dose of 4 g/kg body wt resulted in an increase in portal plasma glucagon concentration. This was associated with an activation of phosphorylase a and a decrease in hepatic glycogen concentration. The present study was undertaken to determine whether similar results...

In normal subjects, ingestion of fat with potato in a morning meal resulted in a decrease in the glucose response. Therefore, we wished to determine whether a fat-induced decrease in blood glucose also would be observed after a second identical meal. In addition, we were interested in determining if fat ingestion with a morning meal would have an e...

Fasted rats were given 4 g/kg glucose orally. Synthase R (active forms), total synthase, and phosphorylase alpha activities, and hepatic glycogen, glucose 6-phosphate (glucose-6P), uridine diphosphoglucose (UDP-glucose), glucose, and plasma glucose concentrations were determined over the subsequent 24 h. The resulting glycogen concentration changes...

Glycogenin is a 37-kDa protein upon which new glycogen molecules are considered to be constructed. Therefore, we were interested in determining its role in liver glycogen synthesis following glucose administration. Twenty-four-hour fasted rats were given 4 g/kg glucose orally. Glycogenin and synthase R activities and glycogen were determined over t...

The cDNA for human liver glycogen synthase was isolated by screening a human liver cDNA library constructed in lambda gt11. The full cDNA was 2912 bp in length. It coded for a protein of 703 amino acid residues with a molecular mass of 80.9 kDa. The number of amino acids was identical to and the deduced amino acid sequence homology was 92% that of...

Glycogen synthase catalyzes the rate-limiting step in glycogen synthesis. Its activity is regulated by a complex phosphorylation-dephosphorylation mechanism and by allosteric stimulators and inhibitors. Two isozymes of synthase, a skeletal muscle type and liver type, have been identified in rabbit and rat tissues using specific polyclonal antibodie...

With progressive ripeness there is a decrease in starch and an increase in free sugar content of bananas. The starch also is considered to be poorly digestible. Therefore, we decided to study plasma glucose, serum insulin, C-peptide, and plasma glucagon responses to bananas with increasing degrees of ripeness. Seven male subjects with untreated non...

Galactose usually is ingested as lactose, which is composed of equimolar amounts of glucose and galactose. The contribution of galactose to the increase in glucose and insulin levels following ingestion of equimolar amounts of galactose and glucose, or lactose, has not been reported in people with non-insulin-dependent diabetes mellitus (NIDDM). Th...

Glycogen synthase catalyzes the transfer of the glucosyl moiety from UDP-glucose to the terminal branch of the glycogen molecule and is considered to be the rate-limiting enzyme for glycogen synthesis. However, under ideal assay conditions, i.e. 37 degrees C with saturating concentrations of UDP-glucose and the activator, glucose-6-P, the maximal c...

In normal subjects, ingestion of butter with potato resulted in considerably lower blood glucose levels but similar or higher insulin concentrations compared with those observed in the same subjects after potato ingestion alone. We determined whether butter ingested with potato would result in a greater stimulation in insulin secretion than ingesti...

Casein hydrolysate administration to fasted rats resulted in a biphasic response of glycogen synthase. Fifteen minutes after the protein meal, synthase R (active form) was increased. This was associated with a transient increase in hepatic glucose and glucose-6-phosphate (G6P) concentrations. Both glucose and G6P are known to stimulate synthase pho...

Ten normal subjects were given 50 g starch, or 50 g starch + 50 g fat as a breakfast meal. The starch was given in the form of potato; the fat was given in the form of butter. The meals were ingested at 8 a.m. Plasma glucose, insulin, C-peptide, and triglyceride concentrations were measured at various time points for 4 hours after each meal. The ne...

The fate of amino acids deaminated following protein ingestion is uncertain. Presumably, the majority of the carbon skeletons of the amino acids are converted into glucose in the liver. In the present study, tritiated glucose dilution tracer studies have been used to determine the effect of a protein meal on the glucose appearance rate in plasma. F...

Test meals with 25 g protein in the form of cottage cheese or egg white were given with or without 50 g glucose to male subjects with mild to moderately severe, untreated, type II diabetes. Water was given as a control meal. The glucose, insulin, C-peptide, alpha amino nitrogen (AAN), glucagon, plasma urea nitrogen (PUN), nonesterified fatty acid (...

Eight men with untreated type II diabetes were given 480 mL water containing 15 g, 25 g, 35 g, and 50 g fructose orally, in random sequence. The same subjects were given the same volume of water as a control. They also were given 50 g glucose on two occasions for comparative purposes. Plasma glucose, urea nitrogen, and glucagon, and serum insulin,...

Information on the metabolic response in people with non-insulin-dependent diabetes mellitus (NIDDM) to ingested individual macronutrients is limited. Available information is reviewed herein. The major absorbed products of carbohydrate-containing foods are glucose, fructose, and galactose. The quantitative effect of these on the plasma glucose and...

Seven healthy, normal-weight subjects were fed breakfasts of 50 g protein, 50 g glucose, and 10, 30, or 50 g protein plus 50 g glucose in random sequence. Plasma glucose, insulin, C peptide, glucagon, nonesterified fatty acids, and alpha-amino nitrogen were then measured from samples obtained over 4 h. The postmeal net area of each response curve w...

In type II diabetic subjects, we previously demonstrated differences in the serum insulin, C-peptide, and glucagon response to ingestion of seven different protein sources when administered with 50 g of glucose. The response was smallest with egg white and greatest with cottage cheese protein. In the present study, we compared the responses to 50 g...

Ten untreated type II (non-insulin-dependent) diabetic subjects were given 15, 25, 35, and 50 g glucose orally. Plasma glucose, insulin, C-peptide, glucagon, urea nitrogen, alpha-amino acid nitrogen, and lactate concentrations were measured, and net 5-h postprandial areas were calculated. The net glucose-area response to the ingested glucose dose (...

An assay for measurement of optimal amounts of glycogen synthase R, the physiologically active form of the enzyme, in liver tissue extracts is described. Tissue extracts enriched in synthase R had a pH profile different from those reported for synthase D and synthase I. In tissue extracts, synthase I had a broad pH optimum but maximal activity was...

The glycogen synthase-mediated reaction is rate-limiting for glycogen synthesis in the liver. Glycogen synthase has been purified essentially to homogeneity and has been shown to be a dimer composed of identical subunits. It is regulated by a phosphorylation-dephosphorylation mechanism, catalyzed by kinases and a phosphatase. The subunits of syntha...

We previously have shown that ingested beef protein is just as potent as glucose in stimulating a rise in insulin concentration in type II diabetic patients. A synergistic effect was seen when given with glucose. Therefore, we considered it important to determine if other common dietary proteins also strongly stimulate an increase in insulin concen...

In fasted rats, casein hydrolysate administration resulted in a marked increase in glycogen synthase I activity, no change in phosphorylase a and a marked decrease in glycogen concentration. This occurred with doses as small as 0.5 g/kg body weight. The major reason for an increase in synthase I appeared to be the reduced glycogen concentration, al...

In seven type II (non-insulin-dependent) diabetic patients, given either 50 g glucose or a mixed meal potentially containing 61 g glucose as starch and sucrose, the postmeal plasma glucose area integrated over 4 h was less after the mixed meal. The insulin area was considerably greater (2.1-fold). The greater increase in insulin could be explained...

Recently there has been an increased interest in determining the circulating glucose concentration after the ingestion of various individual foods and mixed meals. The purpose of these determinations is to systematically rank foods with respect to their quantitative effect on postmeal glucose concentration. Potentially such data could be useful in...

Administration of large doses of insulin to intact rats has been shown to stimulate cardiac glycogen synthase phosphatase activity. This results in an activation of glycogen synthase. However, whether a more physiologic stimulus for insulin secretion also resulted in activation of synthase had not been studied. In the present study, rats were fed g...

The circulating insulin and glucose responses in type II diabetic subjects were determined for 5 h after ingestion of various meals, each containing 50 g carbohydrate. The purpose of the study was to 1) systematically study the insulin response to several different high-starch foods, 2) determine whether this insulin response could be predicted by...

Studies in rats indicated that the major physiologic stimulus for synthesis of liver glycogen is a rise in the portal glucose concentration after ingestion of a meal. Conversely, glycogen degradation in the liver is stimulated by a rise in portal glucagon concentration. In humans, ingestion of carbohydrate lowers the concentration of circulating gl...

Eight normal subjects were given 50 g protein, 50 g glucose, or 50 g protein + 50 g glucose. Plasma glucose, insulin, C-peptide, glucagon, alpha-amino nitrogen (AAN), and nonesterified fatty acid (NEFA) responses were then determined over 4 h. Protein stimulated only a modest insulin rise and the area above fasting baseline was only 28% of that aft...

The plasma glucose and serum insulin responses were determined in untreated Type 2 (non-insulin-dependent) diabetic patients following the ingestion of foods containing sucrose, glucose, fructose or lactose in portions that contained 50 g of carbohydrate. The results were compared to those obtained following the ingestion of pure fructose, sucrose,...

Rats were fed a 70% carbohydrate, 70% protein, 70% fat, or a standard purified diet for 7 d to determine the effect of the diet on heart glycogen synthase response to an acute insulin challenge. Rats fed the high protein or the high fat diets, i.e., the carbohydrate-free diets, exhibited insulin resistance as evidenced by higher plasma glucose leve...

The 12-hr profiles of plasma glucose and insulin concentrations in 26 normal subjects ingesting a diet high in carbohydrate, protein, or fat have been determined. The diets were isocaloric and were given as three identical meals 4 hrs apart. In males the high carbohydrate diet resulted in glucose profiles similar to those obtained with the standard...

Rats were fasted 24, 48 or 72 hours to determine the effect of several days without food on glycogen synthase and synthase phosphatase activity in heart. The basal percentage of synthase I decreased gradually from approximately 20% in fed animals to approximately 6% in rats starved for 72 hours. Glycogen increased progressively from 4.6 mg/g wet we...