Effects of Tolbutamide on Insulin and Glucagon Secretion of the Isolated Perfused Rat Pancreas

Abstract

Insulin and glucagon release in the isolated perfused rat pancreas was measured after stimulation with tolbutamide. The perfusion medium contained either 5.5 mM of glucose or was glucose free. During the first ten min of perfusion with tolbutamide, insulin output rose rapidly while glucagon release was significantly depressed. After a period of prolonged stimulation glucagon began rising again but did not return to initial levels. Following destruction of insulin-producing Bcells by streptozotocin, tolbutamide still caused identical inhibition of glucagon secretion, as in the presence of intact islets.