Suppression of ethanol-induced cardiac hypertrophy by beta-adrenoceptor blockade.
The effects of D,L-propranolol and its resolved epimers on cardiac size in rats given ethanol, or a control diet containing maltose-dextrin, every 8 h by gavage, for 48 h were assessed. Co-treatment with ethanol plus saline for 48 h resulted in increases of approximately 10% in wet and dry heart weights, and in their proportional measures (g/kg body wt). Cardiac protein content was increased similarly. Administration of D,L-propranolol (10, 20 mg/kg), or L-propranolol (5, 10, 20 mg/kg), suppressed the increases in response to ethanol, D-Propranolol (10, 20 mg/kg) was ineffective in attenuating ethanol-induced increases in heart weights and protein content. Values of total cardiac DNA and fractional water content were unaffected by any of the treatments. Adrenaline and noradrenaline levels in urine were elevated during 48 h of intoxication in all rats given ethanol. The results suggest that severe, subacute intoxication with ethanol induces cardiac hypertrophy. Further, the data implies that the hypertrophy is mediated through activation of cardiac beta-adrenoceptors.