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)

Insulin, pancreatic polypeptide, glucagon, oxyntomodulin, and two distinct glucagon-like peptides were isolated from acidic ethanol extracts of bullfrog pancreas by gel filtration followed by high pressure liquid chromatography. The amino acid sequences of pancreatic polypeptide, oxyntomodulin, and both glucagon-like peptides were determined. Frog pancreatic polypeptide contains 36 amino acid residues and has a COOH-terminal phenylalaninamide. It is more homologous with human pancreatic polypeptide (61%) than other characterized members of this family of peptides. Frog glucagon has an amino acid composition identical to the NH2-terminal 29 residues of the larger, more abundant oxyntomodulin and was not sequenced. The finding of a single form of glucagon and oxyntomodulin, but two glucagon-like peptides in frog pancreas extract is similar to that found or deduced for mammals.
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PMID:Isolation of peptide hormones from the pancreas of the bullfrog (Rana catesbeiana). Amino acid sequences of pancreatic polypeptide, oxyntomodulin, and two glucagon-like peptides. 326 Feb 36

In ruminants, the digestive tract and liver metabolism represents a substantial part of the energy requirements. There is almost no net glucose absorption by the gut although it is an energy fuel for the enterocytes. There is a permanent gluconeogenesis, for which the major substrate is propionate. Propionate plays a major role in glucose synthesis is highly effective and propionate metabolism may affect the utilization of other substrates such as lactate. In addition, amino acid metabolism provides a net supply of carbon for gluconeogenesis. However, there is a maximal sparing of the NH2 group (via glutamate release) by the ruminant liver and the energy cost of the conversion of amino acids into glucose is very high. The actual importance of insulin in the regulation of liver metabolism in the ruminant is not entirely understood but glucagon seems not to be a major factor in the stimulation of gluconeogenesis in the fed ruminant. Propionate has a potent effect on anabolism because of its effects on glycaemia and insulin secretion. When glucose requirements are to be enhanced (pregnancy, lactation), even a minor imbalance in the supply of glucogenic substrates may elicit striking physiological changes such as lipomobilization or ketonaemia. In early lactation, insulin secretion is still small in spite of an enhanced food intake. As a result, glucose, fatty acids and amino acids are increasingly channeled towards udder metabolism. Lipogenesis is depressed whereas lipolysis is stimulated by catecholamines. However, excessive glucose and propionate supply may lead to exagerated anabolism and to a drop in milk fat. Thus, a high milk production requires an optimal supply of the three volatile fatty acids (VFA) and it should be emphasized that an improved nitrogen supply has a stimulatory effect on milk production.
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PMID:[Findings on intermediate metabolism in ruminants]. 328 Nov 95

Rats with experimental diabetes due to streptozotocin (75 mg/kg body weight) and free access to food were divided into two groups. One group (n = 9) was optimally treated with insulin (glucosuria less than 4.0 mmol/24 h), using heat treated very long-acting ultralente insulin. The other group (n = 10) was poorly treated with insulin (glucosuria 20-30 mmol/24 h). The nitrogen balance and energy balance of optimally treated diabetic rats was positive and not different from the control group (n = 6). In the poorly treated diabetic rats the nitrogen balance was reduced whereas the energy balance was not different from that of control rats. After 4 weeks the fasting glucagon was: 50 +/- 21 ng/l (mean +/- SEM) in control rats, 62 +/- 18 ng/l in optimally treated diabetic rats and 249 +/- 58 ng/l in poorly treated diabetic rats (p less than 0.01). The capacity of urea nitrogen synthesis determined during alanine loading was: 9.6 +/- 1.0 mumol/(min 100 g body weight) in control rats, 10.6 +/- 1.7 mumol/(min 100 g body weight) in optimally treated diabetic rats and 17.3 +/- 1.3 mumol/(min 100 g body weight) in poorly treated diabetic rats (p less than 0.01). Nitrogen contents of carcass, heart, intestines, liver, and kidneys as determined by Kjeldahl analyses were identical in control rats and optimally treated diabetic rats.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Strict insulin therapy normalises organ nitrogen contents and the capacity of urea nitrogen synthesis in experimental diabetes in rats. 328 51

The dynamic relationship of glucose concentrations and insulin secretion during the postabsorptive state is complex and has been associated with a variety of cyclic rhythms. To study the pattern of insulin and glucose response immediately after a mixed meal, we collected blood every 15 min from 0730 to 1645 h from eight normal resting men (age 24.9 +/- 2.1 yr). They took identically constituted mixed meals at 0800 and 1145 h. Concentrations of glucose and insulin were measured in samples taken throughout the study, whereas levels of C-peptide, glucagon, and alpha-NH2 were determined in samples taken after 1130 h only. Computer-assisted analysis was used to identify significant increments and declines in concentrations and to quantify the coincidence of peaks of glucose, C-peptide, glucagon, and alpha-NH2 with peaks of insulin. Coefficients of correlation between data points were calculated for each individual. The patterns of blood insulin and glucose after breakfast and lunch were different. After breakfast, a single simultaneous peak in insulin and glucose occurred approximately 60 min after starting the meal. In contrast, the pattern after lunch in seven of the eight subjects was clearly biphasic. There were secondary, significant coincident peaks in serum insulin, glucose, and C-peptide occurring 1.75-2.25 h after the meal was served. The secondary peak appeared unrelated to the late absorption of protein because it was not associated with consistent changes in serum alpha-NH2 concentration. Erratic variations characterized the postlunch pattern of glucagon levels, excluding a role for this counterregulatory hormone in the control of the biphasic insulin and glucose response.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Biphasic patterns of peripheral insulin and glucose levels after lunch in normal subjects. 329 77

Vasoactive intestinal peptide (VIP)-immunoreactive nerve fibers have been demonstrated in the rat adrenal cortex in close association with zona glomerulosa cells, suggesting neural regulation of adrenocortical cell function (5). The present studies were undertaken to study the possible role of VIP in the regulation of steroid hormone secretion from the outer zones of the normal rat adrenal cortex. Capsule-glomerulosa preparations, consisting of the capsule, zona glomerulosa, and a small but variable portion of the zona fasciculata, were perifused in vitro. To assess the secretory responsiveness of the capsule-glomerulosa preparation, aldosterone and corticosterone release were measured after stimulation with ACTH and angiotensin II. ACTH (10(-12)-10(-8) M) stimulated dose-dependent increases in aldosterone secretion (1.9- to 36.9-fold increases over basal values) and corticosterone secretion (1.4- to 14.0-fold increases over basal values). Angiotensin II (10(-8)-10(-5) M) stimulated dose-dependent increases in aldosterone secretion (1.6- to 8.8-fold increases over basal values). VIP (10(-6)-10(-4) M) stimulated dose-dependent increases in both aldosterone (1.7- to 41.0-fold) and corticosterone secretion (1.8- to 5.3-fold). However, glucagon and (N-Ac-Tyr1-D-Phe2)GRF-(1-29)NH2, peptides structurally related to VIP, stimulated neither aldosterone nor corticosterone secretion, indicating that VIP effects are likely to be specific for this peptide. It is noteworthy that in this preparation, the stimulation of corticosteroid secretion by VIP at 10(-5) and 10(-4) M was comparable to those by 10(-6) M angiotensin II and 10(-9) M ACTH, respectively. These results support the hypothesis that the VIP innervation of the adrenal cortex may contribute directly to the regulation of adrenal steroidogenesis.
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PMID:Vasoactive intestinal peptide stimulates adrenal aldosterone and corticosterone secretion. 335 77

In primary cultures of rat hepatocytes the glucagon-dependent induction of phosphoenolpyruvate carboxykinase was studied in the presence of putative local hormone and substrate modulators which form clear concentration gradients during liver passage such as adenosine, ketone bodies and ammonia. 1) Adenosine inhibited the induction of phosphoenolpyruvate carboxykinase in a concentration-dependent manner between 50 and 200 microM up to 4 h after glucagon application; AMP had similar, adenine, inosine and guanosine had no effect. Adenosine was almost totally metabolized by the liver cells during the first 4 h of the induction period. The inhibitory action of adenosine was also observed using dibutyryl-cAMP or 8-bromo-cAMP as inducer; it could not be prevented by the adenosine receptor antagonist caffeine nor could it be mimicked by the selective adenosine receptor agonist N6-(phenylisopropyl)adenosine. 2) Acetoacetate suppressed the induction of phosphoenolpyruvate carboxykinase in a concentration-dependent manner between 5 and 20mM during the first 4 h after glucagon addition. beta-Hydroxybutyrate showed no effect. Neither starting with acetoacetate nor with beta-hydroxybutyrate did the cell cultures establish the thermodynamic equilibrium between the two compounds. 3) Ammonia did not affect induction of phosphoenolpyruvate carboxykinase at concentrations up to 2mM. Ammonia was converted to urea within the first 4 h; yet it remained at clearly hyperphysiological concentrations in the medium during that period. It is concluded that the glucagon-dependent induction of phosphoenolpyruvate carboxykinase was modulated by the local hormone adenosine via a mechanism not involving adenylate cyclase and by acetoacetate via an unknown mechanism. The inhibitory action of adenosine may, that of acetoacetate can hardly be physiologically relevant.
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PMID:Modulation of the glucagon-dependent induction of phosphoenolpyruvate carboxykinase by adenosine, but not ketone bodies or ammonia in rat hepatocyte cultures. Possible significance for the zonal heterogeneity of liver parenchyma. 344 1

Gabonase, an enzyme which acts on fibrinogen and factor XIII in uniquely thrombin-like ways, was purified to electrophoretic homogeneity from the venom of Bitis gabonica. On sodium dodecyl sulfate-polyacrylamide electrophoresis, the reduced protein behaved as a single chain with Mr = 30,600. The enzyme contains 20.6% carbohydrate, no free sulfhydryl groups and hence, from amino acid analysis, five disulfide bonds. Its extinction coefficient (E1%1cm) at 280 nm is 9.6. Its pI is 5.3. Gabonase has an active serine residue, is inactivated by phenylmethanesulfonyl fluoride, and has an active histidine which reacts with the chloromethyl ketone of tosyl-L-lysine. Its NH2-terminal amino acid sequence (Val-Val-Gly-Gly-Ala-Glu-Cys-Lys-Ile-Asp-Gly-His-Arg-Cys-Leu-Ala-Leu-Leu -Tyr-) is homologous to the B chain of thrombin. The activity of the enzyme is stabilized by calcium ion. It exhibits strong N alpha-p-tosyl-L-arginine methyl esterase activity, hydrolyzes tripeptide nitroanilide derivatives weakly or not at all, and cleaves no peptide bonds in insulin, glucagon, or the S peptide of ribonuclease. Gabonase clots fibrinogen with a specific activity of 45 NIH thrombin-equivalent units/mg, releasing both fibrinopeptides A and B and showing substrate inhibition at fibrinogen concentrations of 3 mg/ml or greater. The enzyme also activates factor XIII. It is not inactivated by either heparin or hirudin.
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PMID:Thrombin-like enzyme from the venom of Bitis gabonica. Purification, properties, and coagulant actions. 352 80

Two synthetic analogs of CCK-4, Glp-Met-Asp-Phe-NH2 (I) and Pro-Met-Asp-Phe-NH2 (II) reported earlier to stimulate insulin release from the isolated rat pancreatic islets in vitro at concentrations as low as 10(-10) M, have now been found to be totally ineffective as glucagon releasers at concentrations as high as 10(-6) M or higher. It is evident that the replacement of Trp in CCK-4 by Glp and Pro residues leads to peptides which exhibit insulin releasing activity without stimulating the release of glucagon.
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PMID:Synthetic analogs of cholecystokinin terminal tetrapeptide that stimulate insulin but not glucagon release from pancreatic islets. 353 37

Three peptides isolated from the Brockmann bodies of the daddy sculpin, a teleostean fish, have been identified as fragments of one or more proglucagons. The peptide L Q D A E D S S R F D A D D T L A G E A R E L S T P K represents the NH2 terminus of proglucagon (residues 1-27), H S E G T F S N D Y S K Y L E T R R A Q D F V Q W L K N S represents glucagon and H A D G T F T S D V S S Y L N D Q A I K D F V A K L K S G K V represents the glucagon-like peptide at the COOH terminus of the precursor. The fast-atom bombardment mass spectra of the three peptides were consistent with the proposed structures and demonstrated that further posttranslational modifications of the peptides had not taken place. Sculpin glucagon is identical to anglerfish glucagon II but sculpin proglucagon(1-27) and glucagon-like peptide show stronger homology to the corresponding regions of anglerfish proglucagon I than to proglucagon II. The structures of the peptides are suggestive of the action of trypsin-like and carboxypeptidase-B-like enzymes at the site of pairs of basic amino acid residues in proglucagon. The presence of a COOH-terminal lysyl group in proglucagon(1-27) may indicate, however, that the penultimate prolyl residue partially inhibits the action of the carboxypeptidase-B-like activity.
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PMID:Primary structures of three fragments of proglucagon from the pancreatic islets of the daddy Sculpin (Cottus scorpius). 354 98

Insulin and glucagon have been isolated from the Brockmann bodies of the flounder, a teleostean fish, and their primary structures established by automated Edman degradation. The A-chain of flounder insulin shows strong homology to the A-chains from the coho salmon (Oncorhynchus kisutch; 100%) and the anglerfish (Lophius americanus; 95%) but homologies in the B-chain region are weaker (salmon 79%, anglerfish 83%). Flounder insulin B-chain contains the novel sequence Val-Val-Pro-Pro at the NH2 terminus and the highly conserved seryl residue at position 10 (B 9 in mammals) is replaced by an alanyl residue. Flounder glucagon is identical to anglerfish glucagon II but shows four amino acid substitutions compared with salmon glucagon.
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PMID:Primary structure of insulin and glucagon from the flounder (Platichthys flesus). 355 13


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