Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01275 (glucagon)
 26,492 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In ten patients with a femoral shaft fracture, arterial plasma amino acids and glucagon, blood glucose, and serum insulin were measured after an overnight fast on the third, fifth, and seventh days following injury. Ten normal subjects were controls. On all days, concentrations of the key glucogenic amino acid, alanine, were the same in both groups, but levels of another glucogenic amino acid, glycine, were significantly less in the fracture patients. Other amino acid changes following injury were maximal at 7 days, with significant elevations of phenylalanine, methionine, tyrosine, ornithine, lysine, arginine, valine, isoleucine, and leucine. Increased levels of insulin, glucose, valine, isoleucine, and leucine on the fifth and seventh days after injury implied insulin resistance. Plasma glucagon was elevated on the third (p less than 0.05) and seventh (p less than 0.01) days after injury, but the concentrations measured are insufficient to explain the impaired carbohydrate tolerance following a fracture.
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PMID:Arterial plasma amino acids during the first week following femoral shaft fracture. 43 79

The effect on free plasma amino acids before and after infusion of 1 mg glucagon was studied at rest after an overnight fast in seven patients with compensated liver cirrhosis and in seven healthy controls. Total aminoacidaemia in cirrhotic patients is significantly higher than in controls. Elevated basal levels in cirrhotics are found particularly in tyrosine, citrulline, tryptophane, threonine, phenylalanine, and methionine whereas ornithine and serine levels are decreased. Save for the redox couple cystine-cysteine which increases, glucagon elicits an decrease in most amino acids that is proportionate to their initial level. Total aminoacidaemia decreases in controls and cirrhotics by 14.6 and 9.1 per cent respectively. Serum ammonia level rises significantly in both groups, urea increases only in controls, uricaemia remains virtually unchanged.
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PMID:The effect of glucagon on free plasma amino acids in cirrhotics and healthy controls. 63 37

An oral phenylalanine load provokes a significant drop in serum tyrosine levels in children with phenylketonuria [8]. The aim of the present investigation was to examine the response of insulin and glucagon to oral phenylalanine loading as these hormones are known to have a hypoaminoacidaemic effect. Six adult normal weight and healthy men were loaded orally with 0.6 mmol L-phenylalanine per kg body weight after an overnight fast. Serum phenylalanine increased within 10 min after the load and reached a maximum concentration at 30 min. Serum tyrosine increased within 10 min after the load and reached a maximum concentration at 2 h. Plasma glucagon and insulin increased during the first 10 min after the load and reached a peak twice the fasting levels at 30 min after the load. The molar insulin/glucagon ratio remained unchanged during the first 20 min after the load but then declined by 50% at 2 h. Associated with this decline plasma amino acid concentration (except phenylalanine and tyrosine) declined by approximately 15%. The decline was most marked for isoleucine, leucine, methionine and valine. As the hypoaminoacidaemic effect of insulin and glucagon is known to be most marked for these four amino acids plus phenylalanine and tyrosine, the response of insulin and glucagon to a phenylalanine load may influence not only the fate of phenylalanine given but also the blood tyrosine level.
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PMID:Effects of oral phenylalanine load on plasma glucagon, insulin, amino acid and glucose concentrations in man. 66 49

The selective cleavage of peptide bonds by a serine protease from skeletal muscle (SK-protease) was examined using glucagon and neurotensin as substrates. Among the peptide bonds cleaved in these substrates, the most susceptible were Phe-Thr-Ser, Tyr-Leu, Trp-Leu, and Tyr-Ile. These results indicate that the SK-protease hydrolyzed the carboxyl side of aromatic amino acid residues under the experimental conditions. When the amino acid on the carboxyl side of aromatic amino acid residues was serine, threonine or glutamic acid, these peptide bonds, such as Phe-Thr, Tyr-Ser, and Tyr-Glu, were not susceptible to another serine protease from small intestine (SI-protease) under the same experimental conditions. The peptide bond between the arginines of Pro-Arg-Arg-Pro in neurotensin was hydrolyzed by the SI-protease, but not by the SK-protease. Thus the specificity of the SK-protease differs from that of the SI-protease. These results suggest that the specificity of the hydrolytic action of the SK-protease is more like that of bovine chymotrypsin A than like that of porcine chymotrypsin C and of the SI-protease.
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PMID:Selective cleavage of peptide bonds by a serine protease from rat skeletal muscle. 70 Dec 36

Glucagon was iodinated with the lactoperoxidase method at pH 10.0 in the presence of propylene glycol using a substitution of 0.3 g-atom I/mol glucagon. Under these conditions the reactivity of the iodine to tyrosine at position 13 is found to be 4-fold that of the tyrosine at position 10. The amount of diiodotyrosine was less than one-twentieth that of the monoiodotyrosine at either tyrosine residue. Relatively pure monoiodo[125I]tyrosine-13-glucagon can be separated from other iodoglucagons by means of DEAE-chromatography. Such a homogeneous preparation with a known position of the iodine makes it possible to study a specific interaction between the monoiodoglucagon and the glucagon antisera or the glucagon receptor.
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PMID:Preparation of monoiodotyrosine-13-glucagon. 85 7

A protein from porcine gut with 100 amino acid residues (porcine gut GLI-1) and having glucagon-like immunoreactivity has been characterized by partial sequences. The sequence of the C-terminal amino acid residues is -Met-Asn-Thr-Lys-Arg-Asn-Lys-Asn-Asn-Ile-Ala and includes the C-terminal amino acid residue sequence (-Met-Asn-Thr) of porcine glucagon. Evidence is presented that the glucagon sequence -Thr-Ser-Asp-Tyr-Ser-Lys-Tyr- is found in the gut GLI-1 as well. The data support the theory that gut GLI-1 contains the full glucagon sequence and that gut GLI-1 and glucagon are formed from a common precursor.
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PMID:Sequence analysis of porcine gut GLI-1. 88 77

Arterial blood concentrations of insulin, glucagon, and various substrates were determined in six anephric subjects in the postabsorptive state and immediately after hemodialysis. Plasma glucose and serum insulin concentrations were normal, and declined during dialysis. Plasma glucagon was elevated and remained unchanged. There was moderate hypertriglyceridemia before dialysis, but this decreased significantly after administration of heparin just before the start of dialysis, and at the end of dialysis was lowered further into the normal range. Comparison of postabsorptive whole blood concentrations of amino acids with those in normal, healthy adults revealed striking differences. Glutamine, proline, citrulline, glycine and both 1- and 3-methyl-histidines were increased, while serine, glutamate, tyrosine, lysine, and branched-chain amino acids were decreased. The glycine/serine ratio was elevated to 300% and tyrosine/phenylalanine ratio was lowered to 60% of normal. To investigate the potential role of blood cells in amino acid transport, the distribution of individual amino acids in plasma and blood cell compartments was studied. Despite a markedly diminished blood cell mass (mean hematocrit, 20.6 +/- 1.4%), there was no significant decrease in the fraction of most amino acids present in the cell compartment, and this was explained by increases of several amino acids in cellular water. None were decreased. Furthermore, during dialysis, whole blood and plasma amino acids declined by approximately 30% and 40%, respectively, whereas no significant change was observed in the cell compartment. Alanine was the only amino acid whose concentration declined in the cells as well as in plasma. The results indicate (a) significant alterations in the concentrations of hormones and substrates in patients on chronic, intermittent hemodialysis; (b) removal of amino acids during hemodialysis, predominantly from the plasma compartment, with no significant change in cell content; and (c) a redistribution of amino acids in plasma and blood cell compartments with increased gradients of most of the amino acids per unit cell water, by mechanism(s) as yet undetermined.
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PMID:Hormone-fuel concentrations in anephric subjects. Effect of hemodialysis (with special reference to amino acids). 93 88

1. Histidine-pyruvate aminotransferase (isoenzyme 1) was purified to homogeneity from the mitochondrial and supernatant fractions of rat liver, as judged by polyacrylamide-gel electrophoresis and isolectric focusing. Both enzyme preparations were remarkably similar in physical and enzymic properties. Isoenzyme 1 had pI8.0 and a pH optimum of 9.0. The enzyme was active with pyruvate as amino acceptor but not with 2-oxoglutarate, and utilized various aromatic amino acids as amino donors in the following order of activity: phenylalanine greater than tyrosine greater than histidine. Very little activity was found with tryptophan and 5-hydroxytryptophan. The apparent Km values were about 2.6mM for histidine and 2.7 mM for phenylalanine. Km values for pyruvate were about 5.2mM with phenylalanine as amino donor and 1.1mM with histidine. The aminotransferase activity of the enzyme towards phenylalanine was inhibited by the addition of histidine. The mol.wt. determined by gel filtration and sucrose-density-gradient centrifugation was approx. 70000. The mitochondrial and supernatant isoenzyme 1 activities increased approximately 25-fold and 3.2-fold respectively in rats repeatedly injected with glucagon for 2 days. 2. An additional histidine-pyruvate aminotransferase (isoenzyme 2) was partially purified from both the mitochondrial and supernatant fractions of rat liver. Nearly identical properties were observed with both preparations. Isoenzyme 2 had pI5.2 and a pH optimum of 9.3. The enzyme was specific for pyruvate and did not function with 2-oxoglutarate. The order of effectiveness of amino donors was tyrosine = phenylalanine greater than histidine greater than tryptophan greater than 5-hydroxytryptophan. The apparent Km values for histidine and phenylalanine were about 0.51 and 1.8 mM respectively. Km values for pyruvate were about 3.5mM with phenylalanine and 4.7mM with histidine as amino donors. Histidine inhibited phenylalanine aminotransferase activity of the enzyme. Gel filtration and sucrose-density-gradient centrifugation yielded a mol.wt. of approx. 90000. Neither the mitochondrial nor the supernatant isoenzyme 2 activity was elevated by glucagon injection.
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PMID:Purification, characterization and identification of rat liver histidine-pyruvate aminotransferase isoenzymes. 93 69

We have used 125I-labeled vasoactive intestinal peptide (VIP) to study the kinetics, stoichiometry, and chemical specificity with which the labeled peptide binds to dispersed acinar cells prepared from guinea pig pancreas. Binding of 125I-VIP to pancreatic acinar cells was moderately rapid, reversible, specific, saturable, and depended on incubation temperature. Deterioration of 125I-VIP incubated with pancreatic acinar cells at 37 degrees was reflected in a decrease in acid-precipitable radioactivity and in the amount of tracer which could bind to fresh acinar cells. On the other hand, 125I-VIP bound to pancreatic acinar cells appeared to be protected from deterioration. VIP and secretin but not glucagon or COOH-terminal octapeptide of cholecystokinin inhibited binding of 125I-VIP to pancreatic acinar cells. The dose-response curve for inhibition of 125I-VIP binding by VIP or secretin was biphasic and suggested that pancreatic acinar cells have two classes of binding sites: (a) a relatively small number of sites with a high affinity for VIP and a low affinity for secretin, and (b) a relatively large number of sites with a low affinity for VIP and a high affinity for secretin. The difference between the relative affinities of VIP and secretin for the high affinity VIP binding sites appears to be primarily attributable to the NH2-terminal portions of these molecules since synthetic COOH-terminal fragments VIP 14-28, VIP 15-28, and secretin 14-27 were equipotent in inhibiting 125I-VIP binding. On the other hand, secretin 5-27, [6-tyrosine] secretin and native secretin were equipotent in inhibiting binding of 125I-VIP to its high affinity site, and these three peptides were 5 times more potent than secretin 14-27 but 10,000 times less potent than native VIP.
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PMID:Interaction of porcine vasoactive intestinal peptide with dispersed pancreatic acinar cells from the guinea pig. Binding of radioiodinated peptide. 94

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


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