Gastric secretion peptides

Incretins gut hormones that increase glucose-stimulated insulin secretion GLP-1 glucagon-like peptide-1 GDP Gastric inhibitory peptide or glucose-dependent insulino-tropic peptide... 

An important gastric secretion is the hydrochloric acid that performs a number of functions in the stomach. This stomach acid is neutralized by pancreatic bicarbonate ion in the duodenum. Excess acid in the chyme stimulates chemoreceptors in the duodenum. This receptor stimulation elicits reflex inhibition of gastric motility. Excess acid also causes the release of secretin and gastric inhibitory peptide from the duodenum. These hormones contribute to inhibition of gastric contractions so that the neutralization process may be completed before additional acid arrives in chyme from the stomach. 

Gastric inhibitory peptide (GIP) Polypeptide (43 residues) Inhibits gastrin secretion... 

Further pharmacological effects of deltorphins have been demonstrated under various experimental conditions. D-Ala-deltorphin improves memory consolidation in a passive avoidance apparatus in mice this effect is abolished by naltrindole [75]. D-Ala-deltorphin-II caused hypothermia in cold-adapted animals [76]. In contrast to mu opiate agonists, D-Ala-deltorphin-I, at low doses, stimulates respiratory activity in fetal lambs, and this effect is blocked by simultaneous administration of naltrindole [77], The peptide D-Ala-deltorphin-II inhibits diarrhea induced by castor oil and colonic bead expulsion, but it leaves the rate of transit through the small intestine unchanged [78,79]. By the SC route D-Ala-deltorphin-I inhibits acidified alcohol-induced gastric mucosal lesions [80], but by the ICV route, it fails to affect gastric secretion [81], The peptide is involved also in the control of ingestive behavior. It stimulates the intake of food [82] and of sucrose [83],... 

Guilloteau, P., Le Huerou-Euron, I., Chayviaille, J.A., Toullec, R., Legeas, M., Bernard, C., Roger, L., and Mendy, F. 1994. Effect of caseinomacropeptide (CMP) on gastric secretion and plasma gut regulatory peptides in preruminant calves. Reprod. Nutr. Dev. 34, 612—613. 

As linear polypeptides, VIP (vasoactive intestinal polypeptide)105), PHI (peptide HI H = N-terminal His, I = C-terminal lie) lo6107) and GIP (gastric inhibitory polypeptide consisting of 43 amino acids)108) are structurally similar to secretin and glucagon. VIP and PHI act as vasodilators, exert hyperglycemic effects, and affect the smooth muscle of the gallbladder. GIP completely blocks gastric secretion. 

Gastric inhibitory peptide acts via a GPCR on pancreatic (1 cells to promote insulin secretion. The plant natural products gymnemic acid and phloridzin inhibit D-glucose binding to the GI glucose receptor involved in glucose-stimulated GIP secretion. 

Gastric secretion represents a very complex naixture of electrolytes, water, carbohydrates, proteins, peptides, and amino acids, which are partly in solution and partly in more or less stable suspension. The large molecular materials of gastric secretion include enzymes, mucosubstances, serum proteins, peptides and products of proteolytic degradation of gastric proteins and mucoproteins, and blood group substances. 

The presence of food in the stomach evokes gastric secretion. The principal stimuli include distension of the stomach and the presence of amino acids and peptides. Distension of the stomach stimulates mechanor-eceptors that bring about secretion of acetylcholine, hydrochloric acid, and gastrin. 

GIF Peptide Gastrointestinal tract Inhibition of gastric secretion and... 

Gastric inhibitory peptide (GIP) is found in the K cells of the duodenum and jejunum It consists of 43 amino acid residues and occurs in multiple molecular forms. Its secretion is stimulated by the presence of glucose and lipids in the duodenum. It has two main functions ... 

In addition to the decreased intestinal absorption of calcium in uremia, calcium ATPase activity is also low (S6). Many gastrointestinal hormones are found in increased concentrations in uremia. These include gastrin (OlO), cholecystokinin (OlO), pepsinogen I (II), gastric inhibitory peptide (LI), amylase, and trypsin (R17). There is a decrease in the conjugation of cholic to deoxycholic acid (G13) and in the pancreatic secretion of bicarbonate (Oil). Hepatic output of urea is decreased, as is the activity of some urea cycle enzymes e.g., ornithine tran-scarbamylase (T9). The clinical significance of these hormonal and enzymatic perturbations remains to be elucidated. 

An extract of G. sylvestre leaves and purified gymnemic acid inhibited glucose-stimulated gastric inhibitory peptide secretion in rats Sinsheimer et al reported isolation and antiviral activity of the gymnemic acids from G. sylvestre. The strain of Ann Arbor 6/60 of Asian influenza virus was used for in vitro tests and for i vivo studies A/PR8 strain of influenza virus most highly adapted to mice was used. Both jri vitro and n vivo tests indicated significant antiviral activity from the gymnemic acids. In in vivo tests better activity was observed with i.p. administration than with s.c. treatment. 

Bombesin family, a subfamily of the bombesin-like family to which belong bombesin, alytensin and gastrinreleasing peptide, a mammalian counterpart for bombesin. The amphibian peptides bombesin and alytensin are structurally very similar and display biological effects when applied to mammals, such as hypertensive action, stimulation of the uterus and digestive tract, hyperglycemic effect, stimulation on the gastric secretion and increase of insulin levels in peripheral blood. 

The pentapeptide, pentagastrin, has replaced natural gastrin (a heptadeca-peptide) as a diagnostic agent that stimulates gastric secretion. This pentapeptide is butyloxycarbonyl-)8-Ala-Trp-Met-Asp-Phe-NH2. It can be administered as a snuff. 

Gastric inhibitory peptide, GIF a polypeptide hormone (for structure, see Secretin) purified from crude preparations of Cholecystokinin (see). GIF has potent enterogastrone activity, i.e. it inhibits secretion of acid and pepsin by the stomach, and inhibits gastric motility. It possesses no significant secretin or cholecystokinin activity, [J.C. Brown J.R.Drybuigh Canad. J. Biochem. 49 (1971) 867-872]... 

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