A comparison of secretory actions of VIP, secretin and CCK-PZ in the isolated and perfused kitten pancreas.

Secretory actions of VIP (vasoactive intestinal peptide), secretin and CCK-PZ (Cholecystokinin-pancreozymin) were compared in the isolated and perfused kitten pancreas. Perfusion of the isolated kitten pancreas with a solution containing 20 mU/ml CCK-PZ resulted in gradual hyperpolarization of the pancreatic acinar cell. CCK-PZ induced a dose-dependent increase in the pancreatic protein output and a small but definite increase in the flow of pancreatic juice which was also dose dependent upon CCK-PZ. Secretin and VIP induced a dose-dependent increase in the flow but a negligible increase in the pancreatic protein output. The estimated ED50 for VIP was 1.5 nM which was 5 times as large as the estimated ED50 for secretin. A considerable amount of VIP, which corresponded roughly to the activity of exogenous 0.6 nM VIP, was spontaneously released from the isolated kitten duodenum into the portal vein, and this VIP release was nullified during vascular perfusion with a Ca-deficient solution. With respect to these and other results, we will propose a view concerning a possible role of VIP in controlling the function of the exocrine pancreas.