Effect of Repeated Doses of Insulin on Excretion of Pyrocatecholamines

The administration of insulin causes the secretion of epinephrine from the adrenal medulla^1-5 through a central mechanism.^6,7 This effect may be detected by the large increase in the output of the hormone in the urine.^8-10 Release of epinephrine also occurs during the insulin treatment of psychiatric patients, as has long been concluded from the vasopressor changes, pupillary dilation, sweating, and other clinical responses. Because the repletion of the normal adrenal medulla with epinephrine is a slow process, at least in the rat,¹¹ it was considered of interest to determine whether repeated insulinization, as practiced therapeutically in mental patients, affects the balance between formation of epinephrine and its release from the adrenal medulla. The purpose of this paper is to record the finding that the response to insulin, as judged by the excretion of epinephrine, diminishes significantly after a few daily injections of insulin.