Lack of glucagon response to hypoglycemia in long-term experimental diabetic rats.

Glucagon and catecholamine responses to insulin-induced hypoglycemia were investigated in streptozotocin-diabetic rats at various times after streptozotocin administration and in age-matched control male rats. Diabetic rats had basal glucagon levels higher than those in control rats, while basal epinephrine and norepinephrine levels were essentially identical. As the duration of diabetes increased, the glucagon and epinephrine responses to insulin hypoglycemia decreased. The response of control rats was not correlated with age. Increases in plasma norepinephrine values in response to hypoglycemia were similar in both diabetic and control rats. The data indicate a concurrent impaired response of glucagon and epinephrine release in response to insulin-induced hypoglycemia in streptozotocin-diabetic rats as the duration of diabetes prolongs.