Inhibition of insulin release by galanin and gastrin-releasing peptide in the anaesthetized rat.
The present study was designed to determine the effects of intravenously administered galanin or gastrin-releasing peptide (GRP) on glucose- and/or glucose-dependent insulinotropic peptide (GIP)-stimulated insulin release in the anaesthetized rat. Galanin inhibited glucose-stimulated insulin responses in a dose-related manner. Galanin also inhibited insulin release in response to glucose administered with GIP; this effect was due largely to inhibition of the glucose-stimulated component since galanin did not inhibit GIP-stimulated insulin release. Galanin also inhibited insulin responses to ingestion of a mixed meal. GRP inhibited glucose-stimulated insulin responses, and the insulin responses to glucose plus GIP; unlike galanin, GRP inhibited both glucose- and GIP-stimulated insulin release. GRP also inhibited insulin release following ingestion of a mixed meal. The results suggest a possible modulatory role for these neuropeptides in regulation of insulin secretion.
D000758:Anesthesia; D000818:Animals; D004305:Dose-Response Relationship, Drug; D019004:Galanin; D005749:Gastric Inhibitory Polypeptide / Q000494:pharmacology* / Q000502:physiology; D019886:Gastrin-Releasing Peptide; D005768:Gastrointestinal Hormones / Q000494:pharmacology* / Q000502:physiology; D007328:Insulin / Q000378:metabolism*; D000078790:Insulin Secretion; D008297:Male; D010455:Peptides / Q000494:pharmacology* / Q000502:physiology; D051381:Rats; D011919:Rats, Inbred Strains
D005768:Gastrointestinal Hormones; D007328:Insulin; D010455:Peptides; D005749:Gastric Inhibitory Polypeptide; D019886:Gastrin-Releasing Peptide; D019004:Galanin