Pituitary adenylate cyclase activating polypeptide stimulates release of peptide YY

The purpose of these experiments was to examine the effects of the recently discovered gastrointestinal peptide, pituitary adenylate cyclase activating polypeptide (PACAP), and two structurally related peptides, vasoactive intestinal polypeptide and secretin, on release of peptide YY (PYY) in conscious dogs. Intravenous administration of PACAP-27 or -38 stimulated a dose-related release of PYY; PACAP-27 was more potent than PACAP-38. PACAP-stimulated release of PYY was inhibited significantly by atropine, whereas ganglionic or beta-adrenergic blockade with hexamethonium and propranolol treatment, respectively, did not affect PACAP-induced release of PYY significantly (P > 0.05). These results indicate that PACAP-induced release of PYY is cholinergic dependent and that beta-adrenergic tone and ganglionic transmission do not participate in PACAP-induced release of PYY. PACAP may play a role in the neural regulation of PYY release.