Catecholamine-induced necrosis and hypertrophy. Hemodynamic factors.

: Catecholamine-induced myocardial hypertrophy and necrosis in rats have been measured and compared following treatment with different catecholamines. Significant degrees of both hypertrophy (whether measured as biventricular weight or biventricular/body weight ratio) and necrosis (measured by enzyme histochemical techniques on a standardized series of cryostat sections through the apex of each heart) occurred following 10 days' treatment with daily isoproterenol (0.5 or 5 mg/kg s.c.) or dobutamine (5 mg/kg s.c.) (N = 6-12). These agents given to conscious restrained animals lowered blood pressure and increased heart rate for 3, 6, or 1 hr, respectively. Neither hypertrophy nor necrosis occurred after norepinephrine (1 mg/kg) or dopamine (5 mg/kg); both these agents acutely increased blood pressure for about 30 min. Hemodynamic factors may therefore contribute to catecholamine-induced necrosis, which may in turn contribute to the associated hypertrophy.