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

To determine the possible role of altered secretion and effects of insulin in fuel homeostasis during heat exposure, the hormonal and metabolic milieu of three groups of rats were studied. The first was placed at 35 degrees C for 12 days (HE), the second was pair-fed (PF) to the first but maintained at 23 degrees C, and the third was allowed to eat ad libitum at 23 degrees C (C). Plasma insulin, glucagon, glucose, and free fatty acids (FFA), and blood lactate, pyruvate, 3-hydroxybutyrate, and individual amino acids were determined. To further characterize glucoregulation, an intraperitoneal glucose tolerance test (1 mg/g body wt) and isotopic glucose turnover (primed infusion of [3-3H]glucose) were performed. In HE rats, weight was constant for the last third of the period, and metabolic state 4 h after food removal was characterized by euglycemia but hypoinsulinemia, elevated blood pyruvate and FFA, and normal 3-hydroxybutyrate compared with C. Lowered levels of branched-chain amino acids and arginine were found. Fourteen hours after food removal glucose turnover was decreased. However, glucose intolerance accompanied by hyperinsulinemia was also found. Many of these changes were also seen in PF, including constant weight, fasting euglycemia, hypoinsulinemia, elevated FFA, and lowered valine and isoleucine. In contrast, pyruvate concentrations were normal, that of 3-hydroxybutyrate was elevated, and the decrement in glucose turnover was smaller than in HE rats. The glucose tolerance was similar to that of HE but accompanied by hypoinsulinemia. The results in HE suggest decreased energy metabolism, insulin secretion altered in a complex manner, and altered insulin action.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glucoregulatory and metabolic responses to heat exposure in rats. 637 8

Plasma amino acid concentrations and plasma glucagon and serum insulin levels were studied in male patients with compensated alcoholic and nonalcoholic liver cirrhosis. Age, nutritional status, and liver function tests were similar in both groups; none of the patients presented hepatic encephalopathy. Plasma valine and leucine concentrations were lower, and tyrosine, higher in alcoholic than nonalcoholic liver cirrhosis. As a result, the molar ratios of branched-chain amino acids (BCAA) to aromatic amino acids (AAA) were reduced markedly in this group. Although correlation coefficients comparing BCAA/AAA ratios and KICG in alcoholic and nonalcoholic liver cirrhosis were similar, a steeper regression line was observed in alcoholics. Plasma glucagon and proline levels were significantly higher in alcoholic than nonalcoholic liver cirrhosis, the former correlated with AAA concentrations only in alcoholic liver cirrhosis, but not with BCAA levels. These results indicated that alcoholic liver cirrhosis presented a more deranged plasma amino acid pattern than nonalcoholic, and the amino acid imbalances, except for depressed BCAA and elevated proline, were derived, in part, from the hyperglucagonemia.
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PMID:Plasma amino acid imbalance in alcoholic liver cirrhosis. 639 76

The authors have studied the behavior of Aminoacids (AA), GH, Prolactin (PRL), Insulin (IRI) and blood sugar (BS) after fast intravenous injection of 1 mg of Glucagon (G), in eight normal volunteers. The rise in BS levels soon after G. administration at time 10', 20', 30', 45', 60' prompted to consider the initial phase of the experimental to be under G predominance, although IRI did respond to the infusion with a sharp rise, at time 10', 20', 30', 45'. Glycine, serine, threonine, alanine, lysine, phenylalanine and arginine displayed a significant reduction already at time 10' or 20', when G metabolic effects were dominant, a selective G influence on these AA can be supposed. At time 45' and 60' tyrosine, histidine, methionine, valine, leucine, isoleucine, proline, decreased significantly and glycine, serine, threonine, lysine, alanine, phenylalanine, evidenced further reduction. GH and PRL were not affected by the administration of G.
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PMID:[Behavior of blood amino acids after acute administration of glucagon in humans]. 645 90

The amino acids glycine, L-serine, L-asparagine and L-glutamine at 5 mmol/l each markedly increased glucagon release from perifused fetal lamb pancreas tissue, whereas the branched-chain amino acids L-leucine and L-valine had no effect. In contrast, only L-leucine and L-valine had any effect on insulin release. With perifused pancreas tissue from newborn lambs (5-9 days of age) glycine, L-serine, L-asparagine, L-arginine and L-lysine caused a similar marked increase in glucagon secretion with glycine having the greatest effect. These stimulatory effects were attenuated little by addition of glucose (20 mmol/l). L-Leucine had little effect on glucagon release, but was the only amino acid tested which caused marked insulin release in the absence of glucagon. Continuous intravenous infusion of glutamine (3 mmol/h per kg estimated fetal weight) or glutamine and asparagine each at this rate for 2 h into chronically cannulated fetal sheep in utero significantly increased plasma glucagon (P less than 0.05) and insulin (P less than 0.01) concentrations, although the effect on glucagon was not great. The results show how a range of amino acids can influence glucagon and insulin release from the pancreas of fetal and newborn lambs suggesting that physiological changes in plasma amino acid concentrations may contribute to regulation of glucagon and insulin release in utero in this species.
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PMID:Glucagon and insulin release in the lamb before and after birth: effects of amino acids in vitro and in vivo. 676 31

The three acidic proteinases (designated I, II and III, respectively) associated with human erythrocyte membranes were solubilized and purified to an electrophoretically homogeneous state by conventional procedures. Comparative analysis of chemical properties, including amino acid composition and fragmentation by cyanogen bromide cleavage, revealed significant differences among proteinases I, II and III. On the other hand, complete identity among the three proteolytic enzymes was observed on the basis of the peptide bonds specifically hydrolyzed in both glucagon- and phenylalanine-deprived oxidized B chain of insulin. In fact, each of the three proteinases produced splitting of the glucagon molecule between phenylalanine-22 and valine-23, while the susceptible bonds in the oxidized B chain of insulin proved to be those between leucine-15 and tyrosine-16 and between phenylalanine-25 and tyrosine-26, respectively.
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PMID:Differences and similarities among three acidic endopeptidases associated with human erythrocyte membranes. Molecular and functional studies. 699 21

Insulin and glucagon have variable effects in altering arteriovenous differences for amino acids and glucose in liver and muscle. It has not been determined whether these hormones may similarly affect intestine. Acute effects of intraarterial insulin and glucagon were evaluated in in situ, luminally cleansed ileal segments in anesthetized, fasted dogs. Insulin significantly increased th ileal uptake of valine, isoleucine, leucine, tyrosine, threonine, and serine from arterial blood: uptake of these amino acids was approximately doubled 45 min after the end of the insulin infusion. Insulin had no effect on glucose uptake or release. Glucagon decreased ileal glutamate release into mesenteric venous blood 45 min after the end of infusion but the uptake or release of other amino acids and ammonia was not changed. Glucagon did increase mesenteric blood flow acutely and caused a net release of glucose into mesenteric venous blood. The results indicate that insulin and glucagon directly after metabolism of the ileum in vivo.
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PMID:Effects of insulin and glucagon on the uptake of amino acids from arterial blood by canine ileum. 700 41

Previous work has shown that insulin is necessary for lactation. In this study, the short term effects of insulin on the net metabolism of glucose and amino acids by the bovine mammary gland were examined in six experiments in lactating cows. To prevent insulin-induced hypoglycemia from masking the direct effects of insulin, glucose (50--75 g/h) was infused with insulin 12 U/h). The insulin plus glucose infusion (2 h) was followed by a 2-h infusion of glucose alone (75 g/h). Throughout the control and infusion periods, arterial and mammary venous blood samples were obtained to measure venoarterial concentration differences of glucose and amino acids across the mammary gland. During the insulin plus glucose infusion, insulin concentrations increased from basal values of 9 +/- 1 to 38 +/- 6 mu U/ml (mean +/- SE). During glucose infusion alone, the insulin concentration was 15 +/- 2 mu U/ml. Glucagon concentrations were not significantly altered by the treatments. The extraction of glucose by the mammary gland was not altered significantly by insulin, nor was the extraction altered during the infusion of glucose alone. During the infusion of insulin plus glucose and glucose alone, the extraction ratios [(A -- V)/A] of isoleucine, leucine, tyrosine, aspartate, and valine were increased 10--20%. Thus, it appears that insulin does not influence glucose extraction and only moderately may enhance the extraction of some amino acids by the bovine mammary gland.
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PMID:The effect of insulin on net metabolism of glucose and amino acids by the bovine mammary gland. 701 96

Ammonium salts were infused in intact, pancreatectomized, and adrenalectomized dogs to produce coma-inducing amounts of plasma ammonia. Changes in intact dogs included hyperglycemia, hyperglucagonemia, hyperinsulinemia, and decreases in plasma concentrations of glutamine, alanine, threonine, glycine, lysine, valine, proline, serine, arginine, leucine, isoleucine, and methionine. Urinary excretion of catecholamines increased more than 20-fold, whereas plasma hydrocortisone concentrations were essentially unchanged. In pancreatectomized dogs, ammonia infusions caused hyperglycemia, a mild hyperglucagonemia, and no changes in plasma amino acid concentrations, other than a decrease in alanine and an increase in taurine. In adrenalectomized dogs, ammonia infusion resulted in normoglycemia, hyperglucagonemia (comparable with that seen in intact dogs), hyperinsulinemia (2 to 3 times that seen in intact dogs), and decreased plasma concentrations of alanine, isoleucine, leucine, and valine. Finally, propranolol administration did not affect ammonia-induced glucagon and insulin release. The endocrine portion of the pancreas appears to mediate the major effects of ammonia on plasma amino acid values. The effect of ammonia in stimulating glucagon release may occur by an alpha-adrenergic pathway or by direct stimulation of pancreatic islet cells.
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PMID:Effects of ammonia infusion on plasma glucagon, insulin, and amino acids in intact, pancreatectomized, and adrenalectomized dogs. 702 May

Insulin partially inhibits endogenous protein degradation in isolated hepatocytes. The inhibition seems to specifically affect the lysosomal pathway of degradation, since it is not additive to the effects of lysosome inhibitors such as propylamine and leupeptin. The insulin effect is potentiated by intermediate concentrations of amino acids, but is largely abolished at high amino acid concentrations which suppress degradation maximally, suggesting that the hormone may exert its effect indirectly by acting upon the more basal amino acid control mechanism. Glucagon, which stimulates protein degradation, similarly displays its effect only in the presence of intermediate amino acid concentrations. The insulin inhibition is not affected by the aminotransferase inhibitor, aminooxyacetate, indicating that it is not due to interference with amino acid metabolism. Protein synthesis furthermore does not seem to be required, since a significant insulin effect can be seen in the presence of the protein synthesis inhibitor, cycloheximide. The issue is, however, complicated by the fact that cycloheximide itself inhibits protein degradation to approximately the same extent as does insulin. Insulin stimulates uptake of the amino acid alpha-aminoisobutyrate (AIB), but not the uptake of valine, indicating a specific stimulation of 'A'-type transport. Cycloheximide similarly stimulates AIB uptake, without completely obfuscating the transport effect of insulin. Neither protein synthesis, protein degradation, amino acid transport, nor the effects of insulin were affected by cell-to-substratum anchorage (attachment and spreading) in any detectable way.
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PMID:Effects of insulin and anchorage on hepatocytic protein metabolism and amino acid transport. 702 88

Four normal and five insulin dependent diabetic men received a 2 h pharmacologic glucagon infusion (50 ng/kg/min) resulting in plasma glucagon levels (4400 pg/ml) similar to those seen in glucagonoma patients. In normal subjects in whom plasma insulin concentrations rose significantly (239 uU/ml) and the blood level of 15 of the 18 amino acids measured fell significantly. In contrast, in the diabetic men who secreted no insulin in response to glucagon (no rise in C-peptide levels), only 10 of 18 amino acid levels fell significantly. The branched chain amino acids valine, leucine and isoleucine, as well as tyrosine and phenylalanine were among the 8 amino acids which showed no change in response to glucagon in the diabetics. Thus, glucagon appears to have no acute affect on branched chain amino acid levels in man.
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PMID:Effects of pharmacologic hyperglucagonemia on plasma amino acid concentrations in normal and diabetic man. 703 18


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