Characterization of secretin and vasoactive intestinal peptide receptors in rat pancreatic plasma membranes using the native peptides, secretin-(7-27) and five secretin analogues

A comparison has been made of the ability of vasoactive intestinal peptide (VIP), secretin, secretin analogues, and secretin-(7-27) to stimulate adenylate cyclase in rat pancreatic plasma membranes. A parallel study of the capacity of peptides of the VIP-secretin family to compete with 125I-VIP for binding to the same plasma membranes was conducted. This allowed a classification of VIP-secretin receptors into three subtypes: (1) VIP-preferring receptors; (2) high-affinity secretin receptors, and (3) low-affinity secretin receptors. The properties of secretin at high-affinity secretin receptors were likely to reflect a contribution of membranes from centroacinar and duct cells.