Dispensability of both the amide of phenylalanine and the carboxyl group of aspartic acid for the stimulation of gastric acid secretion by gastrin peptides in dogs.
Two derivatives of the C-terminal tripeptide of gastrin devoid of -NH2 from the phenylalanyl residue and of -COOH from the aspartic acid, MBOC-Met.Asn.Phe-OH (I) and MBOC-Met.Asp-OBenz.Phe-OMe (II), stimulated gastric acid secretion in the dog when infused intravenously at doses of 100 to 400 mug/kg-hr. Maximal responses induced by I and II were about 30-40% of that induced by the C-terminal tetrapeptide of gastrin. At a dose of 600 mug/kg-hr, I had an inhibitory action while II initially augmented and then inhibited acid production. Neither the C-terminal amide nor the carboxyl group of the aspartyl residue is essential for the gastric stimulatory activity of gastrin peptides.
D000818:Animals; D001224:Aspartic Acid / Q000494:pharmacology*; D004285:Dogs; D004305:Dose-Response Relationship, Drug; D005750:Gastric Juice / Q000378:metabolism*; D005755:Gastrins / Q000494:pharmacology*; D009842:Oligopeptides / Q000494:pharmacology*; D010446:Peptide Fragments / Q000494:pharmacology; D010649:Phenylalanine / Q000494:pharmacology*; D013268:Stimulation, Chemical; D013270:Stomach / Q000502:physiology
D005755:Gastrins; D009842:Oligopeptides; D010446:Peptide Fragments; D001224:Aspartic Acid; D010649:Phenylalanine