Potentiation of the Hepatic Action of Insulin by Chlorpropamide

In perfused livers of fed rats, chlorpropamide inhibits glucagon-stimulated glucose production by augmenting the action of insulin. This effect is associated with a decrease in cyclic AMP accumulation in liver and perfusate. Alterations in glucose production appear to correlate more closely with changes in the amount of cyclic AMP in the perfusate than with changes in intrahepatic concentration of nucleotide. Potentiation by chlorpropamide of the hepatic action of insulin does not require administration of the drug prior to perfusion. Further, it is demonstrable at concentrations of insulin and glucagon (10−11M) that approximate the normal plasma levels of these hormones.