Decreased Response of Epinephrine and Norepinephrine to Insulin-Induced Hypoglycemia in Diabetic Autonomic Neuropathy

The responses of epinephrine, norepinephrine and other counter-regulatory hormones to insulin-induced hypoglycemia were investigated in 5 diabetics who showed signs of autonomic neuropathy, in 7 age-matched diabetics without autonomic neuropathy and in 7 healthy subjects. The presence of autonomic neuropathy was evaluated by decreased beat-to-beat variation in heat rates during hyperventilation or orthostatic hypotension. Catecholamines were determined by a totally automated plasma catecholamine analyzing system using a two-column system of high performance liquid chromatography. Plasma epinephrine and norepinephrine responses to hypoglycemia in diabetics with autonomic neuropathy were significantly lower than those in diabetics without autonomic neuropathy. Plasma glucagon response in diabetics was apparently attenuated compared to normal controls and there was no significant difference in glucagon response between the two patient groups. Other counter-regulatory hormone responses did not differ among the three groups. The data demonstrate that the responses of plasma epinephrine and norepinephrine to insulin-induced hypoglycemia are impaired in diabetics with autonomic neuropathy.