Inhibition of Insulin and Glucagon Secretion by Somatostatin: Are there Indirect Effects? 1

Abstract

Summary

The inhibitory action of somatostatin upon the endocrine pancreas of dogs was studied as a function of dose and site of administration. Hormone output was measured directly in the pancreaticoduodenal vein. Infusions of somatostatin into the pancreatic artery show that a predictable dose-response relationship exists for this controller of islet function. The high relative potency of somatostatin when administered via a femoral vein or the hepatic portal vein suggests that indirect mechanisms of action are responsible, in part, for the effect of this peptide upon insulin and glucagon output from the pancreas in vivo. It is postulated that, in its indirect effects, somatostatin may inhibit islet hormone secretion by decreasing the circulating levels of several gastrointestinal hormones known to potentiate insulin and glucagon release, or it may elicit an inhibitory neural-pancreatic reflex.