Antagonism Between Glucose and Epinephrine Regarding Insulin Secretion

A dose‐response study of the inhibitory effect of epinephrine on glucose‐induced insulin secretion in man has been performed. The results demonstrate the exquisite sensitivity of the pancreatic β‐cells to epinephrine, as small a dose as 3 mμg/kg/min inducing a 50% inhibition. These studies emphasize the physiological significance of epinephrine for the regulation of insulin secretion. They also show that in previous studies in man and animals supramaximal amounts of epinephrine have been employed. Our results also suggest that the actions of epinephrine and glucose on insulin secretion are competitive. Infusion of aminophylline had only a minor inhibitory effect on the action of epinephrine. Therefore, our data do not permit the conclusion that epinephrine suppresses insulin release exclusively by diminishing the rate of synthesis of cyclic AMP. Other possible mechanisms are discussed.