Fenfluramine inhibits insulin secretion and potentiates glucagon release by the perfused rat pancreas

Abstract

Fenfluramine, an anorectic used in the treatment of obesity, in a final concentration of 1 mM strongly inhibited both phases of insulin release by the perfused rat pancreas. Insulin secretion resumed promptly after cessation of the drug infusion. This concentration of the drug markedly increased glucagon output. The blockade of alpha-adrenergic receptors and the use of antiserotonin agents did not alter the inhibitory effect of fenfluramine on insulin secretion. It is concluded that in the perfused rat pancreas 1 mM fenfluramine acutely inhibits glucose-induced insulin secretion and potentiates glucagon output. The direct effect of fenfluramine on insulin secretion is not related to alpha-adrenergic activity, nor is it mediated by serotonin.