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)

The amino acid sequence of chymodenin, a hormone-like peptide from porcine duodenum is reported. The molecule is known to rapidly alter the proportions of digestive enzymes secreted by the rabbit pancreas in vivo and in vitro, by selection of the specific intra-pancreatic source from which the preset mixture of digestive enzymes is secreted. The sequence is identical to that of cytochrome C-oxidase peptide VII (cCoVII) from bovine heart, with the exception of a substitution of threonine for alanine at position 6 and a second substitution of alanine for threonine at position 71. Disulfide bridges link positions 29-64 and 39-53. cCoVII-chymodenin has a pentapeptide (-Ala-Glu-Gly-Thr-Phe-) near the carboxy-terminus which is immediately preceded by an -Arg-Arg- sequence in the porcine and bovine sequences of cCoVII. This peptide is identical to a pentapeptide found close to the amino terminus of the hormones gastric inhibitory peptide (GIP) and glucagon-like peptide I. The identity to cCoVII means chymodenin as isolated is itself unlikely to be a gastrointestinal hormone. However, the partial commonality of sequence with the glucagon-secretin family immediately adjacent to a pro-hormone-like activation site, and the specific actions on the exocrine pancreas, means that the molecule probably mimics the natural actions of an as-yet uncharacterized member of the glucagon family, which exerts a unique action on exocrine pancreatic secretion.
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PMID:The amino acid sequence of chymodenin, a hormone-like peptide from porcine duodenum, is identical to cytochrome C-oxidase, peptide VII. 217 Oct 45

The effect of specific amino acid groups on renal hemodynamics was examined in seven healthy young volunteers. Each subject received a 3-h intravenous infusion according to one of the following protocols: study 1, gluconeogenic amino acids (Arg, Gly, Pro, Cys, Met, Ser); study 2, alanine alone; study 3, branched-chain amino acids (BCAA, Leu, Ile, Val); or study 4, 0.9% saline. The rise (40-60% above base line) in total plasma amino acid concentration was similar in studies 1-3; no change was observed in study 4. During study 1, glomerular filtration rate (GFR) rose by 16% (from 98 +/- 6 to 114 +/- 8 ml.1.73 m-2.min-1, P less than 0.01), and renal plasma flow (RPF) rose by 28% (from 496 +/- 47 to 638 +/- 70 ml.1.73 m-2.min-1, P less than 0.01). After alanine (study 2) and BCAA (study 3) infusion, there was a slight, although not significant, rise in GFR and RPF; during saline infusion (study 4), GFR and RPF remained unchanged. Plasma insulin and growth hormone did not change significantly in any study protocol. Plasma glucagon rose significantly by 30% in study 1 (from 117 +/- 10 to 151 +/- 13 pg/ml, P less than 0.05) but did not change in studies 2-4. In summary, infusion of mixed gluconeogenic amino acids increases both GFR and RPF, and neither alanine nor BCAA infusion caused a consistent alteration in renal hemodynamics.
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PMID:Effect of specific amino acid groups on renal hemodynamics in humans. 233 Sep 90

Glucagon stimulates 14CO2 production from [1-14C] glycine by isolated rat hepatocytes. Maximal stimulation (70%) of decarboxylation of glycine by hepatocytes was achieved when the concentration of glucagon in the medium reached 10 nM; half-maximal stimulation occurred at a concentration of about 2 nM. A lag period of 10 min was observed before the stimulation could be measured. Inclusion of beta-hydroxybutyrate (10 mM) or acetoacetate (10 mM) did not affect the magnitude of stimulation suggesting that the effects of glucagon were independent of mitochondrial redox state. Glucagon did not affect either the concentration or specific activity of intracellular glycine, thus excluding the possibilities that altered concentration or specific activity of intracellular glycine contributes to the observed stimulation. The stimulation of decarboxylation of glycine by glucagon was further studied by monitoring 14CO2 production from [1-14C]glycine by mitochondria isolated from rats previously injected with glucagon. Glycine decarboxylation was significantly stimulated in the mitochondria isolated from the glucagon-injected rats. We suggest that glucagon is a major regulator of hepatic glycine metabolism through the glycine cleavage enzyme system and may be responsible for the increased hepatic glycine removal observed in animals fed high-protein diets.
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PMID:Regulation of hepatic glycine catabolism by glucagon. 253 45

COOH-terminal decapeptide of gastrin-releasing peptide (GRP-10) is a bombesin-like peptide, which has bioactivities to stimulate gastrin, insulin, and glucagon secretion. We have synthesized an analogue of GRP-10 that inhibits GRP-10's stimulation of insulin secretion both in vivo and in vitro and glucagon secretion in vivo, while potentiating the stimulation of gastrin secretion. The amino acid sequence of this peptide is H-Gly-Asn-Trp-Ala-Ala-Gly-His-Leu-Met-NH2 ([Ala6]GRP-10). Because the stimulation of insulin and gastrin secretion by GRP-10 has been ascribed to a direct effect on B- and G-cells, these findings suggest that there are two subtypes of receptors for bombesin-like peptides in mammalian tissues.
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PMID:[Ala6]gastrin-releasing peptide-10: an analogue with dissociated biological activities. 266 16

In the small intestine, proglucagon is processed into the previously characterized peptide "glicentin" (proglucagon (PG) 1-69) and two smaller peptides showing about 50% homology with glucagon: glucagon-like peptide-1 and -2. It was assumed that the sites of post-translational cleavage in the small intestine of the proglucagon precursor were determined by pairs of basic amino acid residues flanking the two peptides. Earlier studies have shown that synthetic glucagon-like peptide-1 (GLP-1) synthesized according to the proposed structure (proglucagon 71-108 or because residue 108 is Gly, 72-107 amide) had no physiological effects, whereas a truncated from of GLP-1, corresponding to proglucagon 78-107 amide, strongly stimulated insulin secretion and depressed glucagon secretion. To determine the amino acid sequence of the naturally occurring peptide we isolated GLP-1 from human small intestine by hydrophobic, gel permeation, and reverse-phase high performance liquid chromatography. By analysis of composition and sequence it was determined that the peptide corresponded to PG 78-107. By mass spectrometry the molecular mass was determined to be 3295, corresponding to PG 78-107 amide. Furthermore, mass spectrometry of the methyl-esterified peptide showed an increase in mass compatible with the presence of alpha-carboxyl amidation. Thus, the gut-derived insulinotrophic hormone GLP-1 is shown to be PG 78-107 amide.
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PMID:Complete sequences of glucagon-like peptide-1 from human and pig small intestine. 275 90

In our effort to identify the proteolytic specificity of various hemorrhagic toxins isolated from western diamondback rattlesnake venom, hemorrhagic toxin b was isolated in homogeneous form by previously published methods. Hemorrhagic toxin b hydrolyzed glucagon, producing six fragments. The proteolytic sites were identified as Thr(5)-Phe(6), Thr(10)-Ser(11), Asp(15)-Ser(16), Asp(21)-Phe(22) and Try(25)-Leu(26). When oxidized insulin B chain was used, proteolysis occurred at four sites: Asn(3)-Gln(4), His(10)-Leu(11), Tyr(16)-Leu(17) and Gly(23)-Phe(24). The proteolytic specificity of hemorrhagic toxin b is quite different from those of the nonvenom proteases such as thermomycolin, aspergillopeptidase c, alkaline protease from Aspergillus flavus, elastase, subtilisin and papain.
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PMID:Proteolytic specificity of hemorrhagic toxin b from Crotalus atrox (western diamondback rattlesnake) venom. 286 65

Neonatal mice, under fasting conditions, are susceptible to the development of lesions in the arcuate nucleus (AN) of the hypothalamus, with high doses of monosodium L-glutamate (MSG). Feeding of nutrients (e.g., sugars and L-amino acids) has been shown to have a protective effect against the development of these lesions. The purpose of these studies was to elucidate the mechanism of this protective effect. Histopathologic examination of lesions of the AN demonstrated that feeding of weaning mice before subcutaneous administration of toxic doses of MSG suppressed the development of these lesions, as compared to fasted controls. Similarly, the number of necrotic cells in the AN of neonates administered toxic doses of MSG subcutaneously was reduced when D-glucose and L-arginine were administered orally. Atropine obliterated the protective effect of D-glucose. Pretreatments consisting of gastric inhibitory polypeptide (GIP) + oral D-glucose had a protective effect of higher potency than GIP alone. Pretreatments with insulin, anorexigenic peptide (pyroGlu-His-Gly), cholecystokinin, glucagon, bombesin, and substance P (in decreasing order of effectiveness) demonstrated a protective effect against the AN lesion in neonates, whereas somatostatin and beta-endorphin had no effect. Results suggest that the protective effect of nutrients may in part be due to the stimulation of peptide hormone release during the postabsorptive phase. It is postulated that the effect of entero-pancreatic hormone, especially insulin, is to enhance the tolerance of AN neurons of neonatal mice to the toxic dose of L-glutamate.
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PMID:Mealing and related hormone release suppress hypothalamic lesions of neonatal mice by L-glutamate. 288 96

Peptides derived from prosomatostatins I and II and from two distinct proglucagons have been isolated from the pancreas of a teleost fish, the European eel (Anguilla anguilla). The product of prosomatostatin I processing, somatostatin-14, is identical to mammalian somatostatin-14. A 25-amino-acid-residue peptide (Ser-Val-Asp-Asn-Gln5-Gln-Gly-Arg-Glu-Arg10-Lys-Ala-Gly-Cys- Lys15-Asn-Phe-Tyr- Trp-Lys20-Gly-Pro-Thr-Ser-Cys25) is derived from prosomatostatin II. Compared with the corresponding peptides from other teleost fish, the eel somatostatin-25 contains the unusual substitution Pro for Phe at position 22. This peptide was also isolated in a form containing a hydroxylsyl residue at position 20. A 29-amino-acid-residue eel glucagon contains four substitutions relative to human glucagon Asn for Ser8, Glu for Asp15, Thr for Ser16, and Ser for Thr29). In common with mammalian and avian glucagons but unlike most other fish glucagons, the eel peptide possesses a glutamine residue at position 3. A peptide derived from a second proglucagon comprises 36 amino acid residues. A 7-residue C-terminal extension to the glucagon sequence shows structural similarity to the corresponding extension in ratfish (Hydrolagus colliei) glucagon and mammalian oxyntomodulin.
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PMID:Somatostatin-related and glucagon-related peptides with unusual structural features from the European eel (Anguilla anguilla). 290 91

An extensive array of nerve fibers ramify around the afferent blood vessels of the liver and the extrahepatic and intrahepatic biliary pathways, and are thought to be involved in regulation of blood flow. Although the role of sympathetic innervation is established, little is known about the location or role of regulatory peptidergic innervation in the liver. We examined the anatomic distribution of a wide variety of regulatory peptides and several neural antigens by in situ immunohistochemistry in the rat and in man. A rich peptidergic plexus of nerve fibers and ganglion cells was observed around the arterial vessels in both species, with intense immunoreactivity for neuron-specific enolase, neurofilaments, neuropeptide Y, substance P, and vasoactive intestinal polypeptide. S-100 protein immunoreactivity was seen principally in large nerve bundles, suggesting that the majority of nerves in this area were unmyelinated. In contrast, the portal vessels revealed very little peptidergic innervation. No staining was observed with antibodies directed against insulin, glucagon, gastrin, serotonin, met-enkephalin-Arg-Gly-Leu, cholecystokinin, or growth hormone. These findings indicate the presence of a rich, although selective, peptidergic plexus surrounding afferent hepatic blood vessels. This plexus may play an important role in regulation of hepatic blood flow.
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PMID:Neuroendocrine innervation of the hepatic vessels in the rat and in man. 318 22

Anglerfish islet secretory granules have been examined for the presence of an enzyme which could perform C-terminal amidation of glucagon-like peptide II and possibly anglerfish peptide Y. Using [125I]D-Tyr-Val-Gly as substrate, a peptidyl-glycine alpha-amidating monooxygenase (PAM) was detected in islet secretory granule lysates. The enzyme is active between pH 6.0 and 8.5 and exhibits maximal activity near pH 7.0. The islet PAM requires Cu2+, ascorbate, and molecular oxygen for activity. Other divalent metal ions and redox cofactors were tested and found to be inactive in the assay. Even though added Cu2+ and ascorbate are required for detecting islet PAM activity, when these factors were incubated with substrate in the absence of secretory granule lysate, no activity was observed. It was also found that the addition of higher than optimal concentrations of either Cu2+ or ascorbate inhibited amidating activity. The results demonstrate that a PAM is present in secretory granules of anglerfish islet tissue. The characteristics of the islet PAM are similar to those of PAMs identified and characterized in other tissues which produce bioactive C-terminally amidated peptides.
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PMID:Peptidyl-glycine alpha-amidating monooxygenase is present in islet secretory granules of the anglerfish, Lophius americanus. 330 55


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