Effects of adrenergic blockade on the release of insulin, glucagon and somatostatin from the pancreas in response to splanchnic nerve stimulation in cats

Abstract

The effects of .alpha.-, .beta.- or .alpha. + .beta.-adrenergic blockade on arterial plasma concentrations of insulin, glucagon and somatostatin in response to splanchnic nerve stimulation were studied in anesthetized cats. In control experiments splanchnic nerve stimulation caused a marked rise in plasma glucose and glucagon concentrations, and a marked fall in insulin but somatostatin was unaffected. Pretreatment with phentolamine significantly increased basal plasma insulin concentration but the response pattern to splanchnic nerve stimulation was not altered. Propranolol attenuated both the glucose and insulin responses. Combined .alpha.- and .beta.-blockade abolished the hyperglycemia and hypoinsulinemia induced by splanchnic nerve stimulation, whereas the rise in plasma glucagon was not affected. Insulin release from the pancreas and glucose release from the liver are apparently controlled by adrenergic mechanisms whereas pancreatic glucagon and somatostatin secretion is relatively insensitive to splanchnic nerve stimulation in cats.