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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Plasma glucagon levels rose within 1 hr after withdrawal of insulin in 7 juvenile-type diabetics previously kept normoglycemic by prolonged intravenous infusions of insulin. These changes preceded subsequent elevations in plasma alanine levels. Individual rises in plasma glucagon were correlated with elevations in plasma glucose, beta-hydroxybutyrate, free fatty acid, and glycerol levels, suggesting that glucagon may play an important role in the development of diabetic ketoacidosis in man.
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PMID:Plasma glucagon and alanine responses to acute insulin deficiency in man. 111 61

The influence of exercise on leg and splanchnic exchange of substrates was examined in eight insulin-dependent diabetics 24 h after withdrawal of insulin and in eight healthy controls studied at rest and after 40 min of bicycle ergometer exercise at 55-60% of maximal capacity. In four of the diabetic subjects, basal arterial ketone acid levels were 3-4 mmol/ liter (ketotic diabetics) and in the remainder, below 1 mmol/liter (nonketotic diabetics). ,ree fatty acid (FFA) turnover and regional exchange were evaluated with 14-C- labeled oleic acid. Leg uptake of blood glucose rose 13-18 fold during exercise in both the diabetics and controls and accounted for a similar proportion of the total oxygen uptake by leg muscles (25-28%) in the two groups. In contrast, leg uptake of FFA corresponded to 39% of leg oxygen consumption in the diabetic group but only 27% in controls. Systemic turnover of oleic acid was similar in the two groups. Splanchnic glucose output increased during exercise 3-4 fold above resting levels in both groups. In the diabetics, splanchnic uptake of lactate, pyruvate, glycerol, and glycogenic amino acids rose more than twofold above resting levels and was fourfold greater than in exercising controls. Total precursor uptake could account for 30% of the splanchnic glucose output in the diabetic group. In contrast, in the controls, total splanchnic uptake of glucose precursors was no greater during exercise than in the resting state and could account for no more than 11% of splanchnic glucose output. The augmented precursor uptake during exercise in the diabetics was a consequence of increased splanchnic fractional extraction as well as increased peripheral production of gluconeogenic substrates. The arterial glucagon concentration was unchanged by exercise in both groups, but was higher in the diabetics. In the diabetic subjects with ketosis in the resting state, exercise elicited a rise in arterial glucose and FFA, an augmented splanchnic uptake of FFA, and a 2-3 fold increase in splanchnic output of 3-hydroxybutyrate. Uptake of 3-hydroxybutyrate by the exercising leg rose more rapidly than splanchnic production, resulting in a fall in arterial levels of 3-hydroxybutyrate. It is concluded that (a) glucose uptake by exercising muscle in hyperglycemic diabetics is no different from that of controls; (b) splanchnic glucose output rises during exercise to a similar extent in diabetics and controls, while uptake of gluconeogenic substrates is markedly higher in diabetics and accounts for a greater proportion of total splanchnic glucose output; (c) exercise in diabetic patients with mild ketosis is associated with a rise in blood glucose and FFA levels as well as augmented splanchnic production and peripheral uptake of ketone bodies.
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PMID:Splanchnic and leg exchange of glucose, amino acids, and free fatty acids during exercise in diabetes mellitus. 113 76

Six normal subjects received 10 g of alanine both orally and as a 60-min intravenous infusion. In both studies blood samples for hormones and substrates were obtained every thirty minutes for 2 1/2 hour. Significant increases in whole blood levels of threonine, serine, glutamine, proline, glycine, and alpha-amino-n-butyric acid were found, which were mainly due to increases of these amino acids in the plasma compartment. In contrast, whole blood levels of leucine, valine, and isoleucine declined, mainly due to increases in the cell compartment. Plasma glucagon levels increased in both studies while insulin levels rose significantly only during the oral study. Plasma free fatty acids and blood glycerol levels declined while lactate and pyruvate increased. Glucose concentration did not change during both tests. These data suggest that the administration of large quantities of alanine is capable of inducing significant alterations in levels of other amino acids and substrates as well as changing hormone levels.
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PMID:Alanine-induced amino acid interrelationships. 116 33

Studies were performed in 6 healthy, male volunteers to explore the effect of a work load on the blood concentrations of catecholamines in relation to pulse rate and blood pressure and the blood levels of pancreatic glucagon, insulin, growth hormone, glucose and glycerol. The work load consisted of 300 kpm/min for 5 min, followed by 600 kpm/min during the next 5 min and 900 kpm/min under a third 5 min period. The work load resulted in a marked increase in noradrenaline and adrenaline at 10 and 15 min of exercise. The pulse rate, the systolic pressure and the mean blood pressure were correlated to the blood levels of both adrenaline and noradrenaline. In spite of the rather marked activation of the sympathetic nervous system no increase occurred in glucagon as measured under exercise and up to 60 min after its completion. In 4 of the subjects the work load was followed by a prompt growth hormone response. The same 4 subjects also showed a marked increase in catecholamines. The 2 remaining subjects presented no change in growth hormone and their increase in catecholamines was relatively minor. Glycerol increased significantly during work and there was a positive correlation between the values recorded for glycerol and adrenaline. No significant changes occurred in blood sugar or insulin during work.
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PMID:The influence of short term submaximal work on the plasma concentrations of catecholamines, pancreatic glucagon and growth hormone in man. 117 88

Insulin antagonism characterizes infection, but the mechanism is unknown. Previous studies have been performed during the acute catabolic stage of infection, and the resultant metabolic changes reflect this decreased food intake and weight loss. To delineate metabolic alterations due to infection itself, rats with pyelonephritis induced by tail-vein injection of 1 ml. of Streptococcus faecalis (10(9) bacteria per milliliter) were studied two weeks later during a period of near-normal weight gain and food intake. Fasting growth hormone concentrations (nanograms per milliliter) in the pyelonephritic rats were nearly five times normal (45.8 vs. 9.9). Intra-arterial glucose and insulin tolerance tests were impaired. Early glucose-induced insulin release was depressed. Fat pads from infected rats manifested higher basal lipolysis per cell. Glycerol-mediated gluconeogenesis by liver slices was decreased. This pathway was unaffected by insulin in infected rats but readily inhibited in control rats. The following metabolic parameters were similar in control and infected animals: (in vivo) fasting concentrations of plasma glucose, free fatty acids, triglycerides, total corticoids, creatinine, insulin, glucagon, molar ratios of insulin and glucagon, glucose and insulin responses to tolbutamide, and glucagon and free fatty acid suppression after glucose; (in vitro) glucose metabolism by muscle and fat, epinephrine- and theophylline-stimulated lipolysis and re-esterification by epididymal fat pads, fasting hepatic glycogen content, glucose production by liver slices with and without alanine. No plasma insulin antagonist was found in the infected rats. Metabolic alterations in infected rats can be demonstrated independently of the associated catabolism. Increased growth hormone secretion cannot explain all of these changes.
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PMID:Metabolic studies in the pyelonephritic rat. 117 60

The net hepatic metabolism of amino glycerol, lactate, and pyruvate was determined in conscious fed sheep by multiplying the venoarterial concentration differences by the hepatic blood or plasma flow. In each experiment several sets of control blood samples were taken; glucagon or insulin then was infused intraportally for 2 h during which additional samples were taken. Four types of experiments were performed: 1) glucagon infusion (150 mug/h) into normal sheep, 2) glucagon infusion (100 mug/h) into insulin-treated alloxanized sheep, 3) insulin infusion (1.17 U/h) into normal sheep, and 4) insulin plus glucose infusion (12.3 mmol/h) into normal sheep. The second group of experiments was performed to prevent reflex hyperinsulinemia, and the fourth was performed to prevent reflex hyperglucagonemia. Glucagon directly stimulated the net hepatic uptake of alanine, glycine, glutamine, arginine, asparagine, threonine, serine, and lactate. Glucagon also stimulated lipolysis in adipose tissue. Insulin, on the other hand, appeared to have a lipogenic effect on adipose tissue and to stimulate directly the uptake of valine, isoleucine, leucine, tyrosine, lysine, and alanine only at extrahepatic sites. The study showed that, in sheep, the effects of glucagon primarily are on liver, and insulin's effects primarily are on skeletal muscle and adipose tissue where it promotes protein and lipid synthesis.
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PMID:Effects of glucagon and insulin on net hepatic metabolism of glucose precursors in sheep. 120 Jan 53

The role of glucagon in regulating peripheral tissue metabolism in man was assessed in the present studies. To do this, glucagon was infused for two hours into the brachial artery to produce a high but physiologic increment in the glucagon content of arterial blood supplying ipsilateral tissues. Metabolic effects on muscle and on subcutaneous adipose tissue plus skin were sought in seven overnight-fasting subjects and seven subjects starved briefly (60 hours). In the overnight-fasted group the infusion increased bassl glucagon concentration by 1,216 pg./ml. but was without effect on forearm tissue metabolism of glucose, lactate,glycerol, or amino acids. Starvation significantly reduced basal insulin (11.0 to 7.4 muU./ml.) and increased endogenous glucagon (116 to 134 pg./ml.). Basally, there was substantial ketone utilization and a decrease in glucose consumption by both muscle and subcutaneous adipose tissue plus skin. The glucagon infusion increased basal glucagon by 784 pg./ml. Muscle balances of glucose, lactate, acetoacetate, amino acids, and glycerol were unaffected. The metabolism of glucose, lactate, acetoacetate, glycerol, and free fatty acids by subcutaneous adipose tissue plus skin was also unchanged. It is concluded that physiologic increments of glucagon lasting two hours are without effect on forearm tissues in overnight-fasted and briefly starved man.
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PMID:Metabolism of forearm tissues in man. Studies with glucagon. 124 74

Plasma lipid and hormone levels have been measured during 72 hours total starvation in nine healthy subjects, to assess the relative importance of hormones and substrates in human triglyceride metabolism. Plasma free fatty acid and glycerol concentrations rose steadily on each day of starvation. Plasma triglyceride concentrations rose on the second and third days, from a control level of 649 +/- 67 mg/1 to a maximum of 1001 +/- 66 mg/1. Plasma cholesterol concentrations remained unchanged while glucose concentrations fell and insulin did not change. Plasma glucagon (C-GLI) levels doubled while secretin levels, reported previously, rose threefold. It is suggested that during acute starvation the rise in triglyceride concentration results from the increased availability of free fatty acids, and that elevated secretin and glucagon levels enhance lipolysis and hence provide substrates for triglyceride synthesis.
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PMID:Triglyceride metabolism in acute starvation: the role of secretin and glucagon. 126 85

Gluconeogenesis was studied in 3 cases of persistent neonatal hypoglycaemia. In 2 of the cases the labelling of blood glucose after i.v. injection of 1415C-alanine was reduced. In these 2 patients only 1.3-5% of the injected radioactivity was recovered in blood glucose, compared with 10% in normoglycaemic patients. The labelling of glucose from 14C-glycerol, as studied in one case, was not reduced. In this patient the labelling of blood glucose from C-alanine was improved after subtotal resection of the pancreas, and with increasing age. By the time of the isotope studies the plasma insulin was normal in all patients, and no deficiency of glucagon secretion could be detected after stimulation with an alanine load. A quantitative amino acid analysis of plasma revealed a moderate increase of some of the glucogenic amino acids. The results were interpreted as a deficiency of gluconeogenesis, probably at the phosphoenolpyruvate carboxykinase or pyruvate carboxylase step.
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PMID:Gluconeogenesis in infancy and childhood. II. Studies on the glucose production from alanine in three cases of persistent neonatal hypoglycaemia. 127 63

A fast and direct effect of dexamethasone on liver metabolism is reported. In the perfused rat liver, addition of dexamethasone directly to the perfusate is followed by an increase in the level of free fatty acids (FFA) and glycerol. These effects of dexamethasone are evident within 30 minutes of hormone administration. The response to dexamethasone in livers from normal and adrenalectomized rats is similar. While dexamethasone and glucagon both had a lipolytic effect, these effects are not additive.
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PMID:A fast in vitro effect of glucocorticoids on hepatic lipolysis. 127 18


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