Effect of corticosterone on insulin and glucagon secretion by the isolated perfused rat pancreas

The in vitro effect of corticosterone in insulin and glucagon secretion has been examined in the isolated perfused rat pancreas preparation. COrticosterone at physiological concentrations was found to inhibit acutely and strongly the secretion of insulin induced by both glucose and arginine and to potentiate the output of glucagon in a glucose-free medium or when induced by arginine. Phentolamine, an alpha-adrenergic blocking agent, diminished the strong inhibitory effect of corticosterone on insulin secretion. The present results demonstrate that corticosterone has direct effects on pancreatic islet cells, and they suggest that the inhibition of insulin secretion is to some extent related to the alpha-adrenergic receptors.