Catecholamine-induced myocardial necrosis in experimental diabetes mellitus.

The pathogenesis of the cardiomyopathy associated with diabetes mellitus is unknown. Among several suggested mechanisms, myocardial necrosis induced by endogenous catecholamines may play a role. Therefore, the sensitivity of the heart to the effect of varying doses of isoproterenol hydrochloride and norepinephrine bitartrate was examined in diabetic and control rats given streptozocin. The dose of isoproterenol hydrochloride ranged from 0.008 to 30 mg/kg of body weight. Norepinephrine bitartrate was given in doses from 0.2 to 1.0 mg/kg of body weight. Each dose was given twice, 24 hours apart. Animals were killed 48 hours after the first dose, and their hearts were examined pathologically. Diabetes did not significantly alter the pathological response of the heart to either drug. We conclude that the diabetic heart is not intrinsically hypersensitive to catecholamines.