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)

Peptides and non-peptides acting as vasoconstrictors or vasodilators have been tested in dog isolated carotid arteries with and without endothelium and in the presence and absence of a variety of antagonists and inhibitors of endogenous substances. It has been found that substance P and several other tachykinins, bradykinin, neurotensin, bombesin and acetylcholine relax the isolated artery only when the endothelium is present, while VIP, isopropylnoradrenaline, adenosine, histamine, prostaglandins E1 and E2, glucagon and insulin relax and angiotensin, vasopressin, oxytocin, 5-HT and noradrenaline contract the isolated vessel, no matter whether the endothelium is present or not. Peptide and non-peptide antagonists have been used with success to show that vasoconstrictors and vasodilators act on specific receptors, since their effects are reduced in the presence of antagonists, specific for one or another of the various agents. Inhibitors of the arachidonic acid cascade only reduce the effect of acetylcholine, suggesting that at least two different mechanisms are involved in the endothelium-mediated relaxation of arterial smooth muscles to peptide and non-peptide agents. The results summarised in this paper suggest that the site of action of several vasodilators is the endothelium, while other vasodilators and all the vasoconstrictors influence the arterial vessels tone presumably by acting on the smooth muscle cells.
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PMID:Effects of peptides and non-peptides on isolated arterial smooth muscles: role of endothelium. 393 Feb 67

The effects of bombesin on gastric acid secretion from the Heidenhain pouch (HP), intraduodenal pH and gastroenteropancreatic (GEP) hormone levels were compared between 4 dogs with antrocolic transposition (ACT) and 4 non-ACT dogs. Bombesin, infused i.v. at a dose of 0.5 microgram/kg for one hr, produced a significant increase in gastric acid secretion from HP and a decrease in intraduodenal pH in both groups. However, these changes were more marked in ACT dogs. The intravenous infusion of bombesin also produced, in both groups, an increase in the plasma levels of gastrin, secretin, motilin, insulin, glucagon and pancreatic polypeptide (PP) with a different shape of curve for each hormone. Comparison between the two groups showed significantly greater plasma gastrin, secretin and insulin responses, and smaller plasma PP response in ACT dogs than in non-ACT dogs. These results demonstrate that the mechanism of GEP hormone release by bombesin may be complex and hormone responses to infusion of bombesin are influenced in a state of acid hypersecretion induced by ACT.
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PMID:Gastric acid secretion, intraduodenal pH and gastroenteropancreatic hormone release to bombesin in antrocolic transposition dogs. 398 57

There is evidence for involvement of gastrointestinal hormones in pathogenesis of obesity and reports on lipolytic activity in animals. The in vitro lipolytic activity of these hormones was tested in human adipocytes. Vasoactive intestinal polypeptide, glucagon, secretin, human gastrin I, gastrin releasing polypeptide, gastric inhibitory polypeptide, pancreatic polypeptide, motilin, bombesin, neurotensin, C-peptide, as well as cholecystokinin did not stimulate lipolysis significantly above basal. These results indicate that the involvement of these hormones in obesity in man might not be due to a direct lipolytic effect on the human adipocyte.
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PMID:Glycerol release from incubated human adipocytes is not affected by gastrointestinal peptides. 401 16

Historically, the enterochromaffin cell was the first endocrine cell type detected in avian gut; subsequently, a number of types of such cells were distinguished on the basis of the ultrastructural features of the secretory granules. More recently, immunocytochemical procedures have revealed somatostatin-, pancreatic polypeptide (PP)-, polypeptide YY-, glucagon-, secretin-, vasoactive intestinal peptide (VIP)-, gastrin-, cholecystokinin-, neurotensin-, bombesin-, substance P-, enkephalin-, motilin-, and FMRFamide-like immunoreactivity in avian gastrointestinal endocrine cells. Most endocrine cells are located in the antrum; there are a number in the proventriculus and small intestine but few in the gizzard, cecum, and rectum. Several avian gastroenteropancreatic hormones, including glucagon, VIP, secretin, bombesin, neurotensin, and PP, have been isolated and sequenced. They resemble the equivalent mammalian peptides in terms of molecular size but differ in amino acid composition and sequence; some (e.g., VIP) differ only in minor respects, others (e.g., secretin) more radically. Gastrointestinal endocrine cells appear late in development; available data indicate that few types are recognized by either immunocytochemistry or electron microscopy before 16 days of incubation. Experimental evidence has shown that at least the majority of gut endocrine cells are of endodermal origin and are not derived from the neural crest or neuroectoderm as earlier proposed. In early embryos, the progenitors of gastrointestinal endocrine cells are more widespread than are the differentiated cells in chicks at hatching. This, along with other observations, raises the question of factors that might influence the differentiation of gut endocrine cells.
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PMID:Gastrointestinal hormones in birds: morphological, chemical, and developmental aspects. 608 44

A radioassay for nonoxidized methionine in peptides is described; it has advantages over other methods currently used because of its simplicity, sensitivity, accuracy, and applicability to individual peptide components in mixtures and to many samples at a time. Methionyl residues were S-carboxymethylated with iodo[2-14C]acetic acid; iodo[2-3H]acetic acid did not provide a stable radioactive tracer. The labeled peptide was isolated by carboxymethylcellulose chromatography or by isoelectric focusing (IEF) or electrophoresis in polyacrylamide gel, and its radioactivity measured. The assay was applied to corticotropins, alpha-melanotropin, bombesin, glucagon, substance P, parathormone, and calcitonin. Twenty-four to thirty samples were conveniently analyzed at a time with a lower detection limit of less than 1 nmol of methionine per sample. The accuracy of the assay, assessed also by reverse-phase high-performance liquid chromatography, is a consequence of its precision, the specificity of the reaction with iodoacetic acid, and the use of an appropriate standard of the peptide being assayed. Methionine was identified, and could be estimated, in individual peptide components of a mixture by using IEF to separate simultaneously the labeled peptide from iodo[2-14C]acetic acid and from other peptide and protein components. This was facilitated by a convenient method for detecting and quantifying these peptides after IEF. The assay is particularly useful for several peptide hormones whose biological activity depends on their sole methionine residue being in a nonoxidized state. It can be used for monitoring their isolation or synthesis and their stability during processing and storage, as well as for evaluating differences in biological potency between preparations and analogues.
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PMID:A radioassay for nonoxidized methionine in peptides. A method for identifying (after isoelectric focusing) and for estimating biologically active forms of corticotropin and other hormones. 609 26

The effects of somatostatin-14 (S14) and somatostatin-28 (S28), a novel intestinal peptide containing somatostatin tetradecapeptide in its C-terminal position, on the bombesin-stimulated release of gastrin, insulin, and glucagon were tested. On iv infusion of bombesin, the increase in the level of glucagon was seen to be twice that of gastrin, and the insulin increase was 8 times that of gastrin. Plasma concentrations of somatostatin were not modified. S14 and S28 inhibited the release of gastrin, insulin, and glucagon; insulin release was inhibited most effectively, with glucagon release next, and gastrin release least inhibited. Based on the exogenous dose needed to produce equal effects, S28 was more potent than S14 on a molar basis, but based on the plasma concentrations needed to produce equal effects, S14 and S28 were equipotent.
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PMID:Effects of somatostatin-14 and somatostatin-28 on bombesin-stimulated release of gastrin, insulin, and glucagon in the dog. 611 46

Somatostatin-28 (SS-28) is 380 times as potent as somatostatin-14 (SS-14) to inhibit acutely insulin secretion induced by arginine in vivo; SS-28 is only 3 times as potent as SS-14 to inhibit glucagon secretion induced by arginine. D-Trp substitution in position 28 of SS-28 increase potency to 2600 times that of SS-14 for inhibition of arginine induced insulin secretion. SS-28 in 10 and [D-Trp22]-SS-28 is 100 times as potent as SS-14 to act within the central nervous system to inhibit bombesin induced hyperglycemia. SS-28 compared to SS-14 shows pancreatic beta-cell and brain selectivity of action.
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PMID:Somatostatin-28: selective action on the pancreatic beta-cell and brain. 611 38

Using histological and immunhistochemical techniques, nine endocrine cell types were observed in the mucosa of the gastrointestinal tract of the toad, Bufo regularis, viz. enterochromaffin, somatostatin, glucagon, pancreatic polypeptide (PP), secretin, gastric inhibitory peptide (GIP), gastrin-C-terminal pentapeptide (GTPP), neurotensin and bombesin cells. The enterochromaffin cells were distributed throughout the gastrointestinal tract except the rectum. Somatostatin, glucagon, PP, secretin, GIP and GTPP cells were observed both in the stomach and in the small intestine. Neurotensin cells were seen only in the ileum and bombesin cells only in the pyloric and antral parts of the stomach. Immunostaining of consecutive sections did not reveal more than one polypeptide hormone in any of these cell types. It is concluded from the present results that the toad gastrointestinal mucosa contains endocrine cell types that are more or less homologous to those in the mammal alimentary tract, though some of them exhibit a different topographic distribution.
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PMID:Histological and immunohistochemical studies of the endocrine cells of the gastrointestinal mucosa of the toad (Bufo regularis). 611 16

Bombesin was injected into the cerebral ventricle of male rats anesthetized with urethane to study its effect on plasma levels of immunoreactive somatostatin (IRS) in hypophysial portal and jugular blood. An intraventricular injection of bombesin (0.2 and 2 micrograms/rat) caused a significant and dose-related increase in plasma IRS in hypophysial portal blood but not in jugular blood. Although bombesin placed into the cerebral ventricle is known to stimulate glucagon and epinephrine release, an iv injection of glucagon (100 micrograms/100 g BW) or epinephrine (2.5 micrograms/100 g BW) did not cause any significant changes in plasma IRS levels in hypophysial portal and jugular blood, suggesting that these substances do not mediate bombesin stimulation of portal IRS release. Pretreatment with naloxone (75 micrograms/100 g BW, iv) failed to affect the portal IRS release induced by bombesin (2 micrograms/rat), indicating that the opiate receptor is not likely to be involved in this reaction. To ascertain whether IRS released by bombesin into hypophysial portal blood is biologically active, the effect of bombesin on the plasma GH level was then examined. Bombesin (2 micrograms/rat) injected intraventricularly completely suppressed the rise of plasma GH after the intraventricular injection of beta-endorphin (1 microgram/rat) or the iv injection of prostaglandin E1 (5 micrograms/100 g BW). Bombesin thus appears to stimulate the secretion of IRS, and probably biologically active somatostatin as well, from the hypothalamus into hypophysial portal blood, thereby inhibiting GH release from the anterior pituitary.
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PMID:Stimulation by bombesin of immunoreactive somatostatin release into rat hypophysial portal blood. 611 30

The present study was designed to determine the effects of intravenously infused bombesin (10 ng/kg/min) upon basal and postprandial plasma somatostatin-like immunoreactivity (SLI), glucagon, insulin and triglyceride levels in normal (n = 12) and chemically sympathectomized (n = 11) dogs. Basal plasma SLI, glucagon and insulin levels rose significantly during the infusion of bombesin in the normal dogs, and this was not altered by chemical sympathectomy. Bombesin infusion enhanced the postprandial SLI response, while attenuating the postprandial glucagon response by 50% and the insulin response in the early postprandial phase of the meal. Sympathectomy did not significantly alter the basal levels of these polypeptides, but augmented the postprandial plasma SLI response during the first 90 min, and reduced the postprandial glucagon response during the infusion of bombesin. The postprandial insulin response was not affected by sympathectomy. In both normal and chemically sympathectomized dogs the rise in postprandial triglyceride levels was attenuated by bombesin infusion.
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PMID:Effect of bombesin upon plasma somatostatin-like immunoreactivity, insulin and glucagon in normal and chemically sympathectomized dogs. 611 14


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