Effect of Intrapancreatic Administration of Vasoactive Intestinal Peptide upon the Release of Insulin and Glucagon in Dogs

Abstract

To investigate the effect of vasoactive intestinal peptide (VIP) on the endocrine function of the pancreatic islet, experiments with a local circulation of the pancreas were performed in anesthetized dogs. VIP was infused into the pancreatic artery in doses of 20, 100, 200 and 400 ng for 10 min. Blood glucose level in the femoral artery did not change during and after the infusion of VIP. Since VIP is known to increase blood flow, a circuit was made in the pancreatic vein and blood flow rate of the pancreatic vein was calculated from the time necessary to obtain a volume of blood. Blood flow rate of the pancreatic vein did not change throughout the experiment with graded doses of VIP. Plasma insulin in the pancreatic vein increased transiently following the infusion of 20 ng VIP but a constant and significant rise of plasma insulin was observed in the experiment with 400 ng of VIP. To the contrary, plasma glucagon in the pancreatic vein increased significantly after the infusion of VIP in doses of 20 to 400 ng for 10 min. The changes in the secretion of these hormones were similar to those in the plasma levels of these hormones in the pancreatic vein. From the present experiment it is concluded that VIP even in a small dose, which does not induce hyperglycemia or increase in blood flow, stimulates the secretion of insulin and glucagon from the pancreas.

Key words

Insulin Release - Glucagon Release - VIP