The Neuropeptide Pituitary Adenylate Cyclase–Activating Polypeptide and Islet Function
Abstract
The neuropeptide pituitary adenylate cyclase–activating polypeptide (PACAP) is ubiquitously distributed in both the central and peripheral nervous systems and exerts a variety of effects. PACAP is a neuropeptide in pancreatic islets, where it has been suggested as a parasympathetic and sensory neurotransmitter. PACAP stimulates insulin secretion in a glucose-dependent manner, by an effect executed mainly through augmenting the formation of cAMP and stimulating the uptake of calcium. Accumulating evidence in animal studies points to a physiological importance of PACAP in the regulation of the insulin response to feeding. This review summarizes the current knowledge of islet actions and mechanisms and the function of PACAP.
Footnotes
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Address correspondence and reprint requests to Bo Ahrén, Department of Medicine, Lund University, B11, BMC, SE-221 84 Lund, Sweden. E-mail: bo.ahren{at}med.lu.se.
Received for publication 23 February 2001 and accepted in revised form 18 June 2001.
AC, adenylate cyclase; CGRP, calcitonin gene–related peptide; GIP, gastric inhibitory polypeptide; GLP-1, glucagon-like peptide 1; IP, inositol phosphate; PACAP, pituitary adenylate cyclase activating polypeptide; PI 3-K, phosphatidylinositol 3-kinase; PK, protein kinase; PLC, phospholipase C; PRP, PACAP-related peptide; RT-PCR, reverse transcriptase–polymerase chain reaction; VIP, vasoactive intestinal peptide.
