RATES OF PROTEIN-SYNTHESIS IN DIFFERENT REGIONS OF THE NORMOTENSIVE AND HYPERTROPHIED HEART IN RESPONSE TO ACUTE ALCOHOL TOXICITY

The objective of study was (a) to investigate whether protein synthesi s in different regions of the heart (i.e. left and right atria, left a nd right ventricles) expressed equal sensitivity to acute ethanol dosa ge, and (b) to ascertain whether concomitant cardiac abnormalities (i. e. experimental hypertrophic heart disease) exacerbated these response s. Acute ethanol dosage (75 mmol/kg body weight, i.p.) to mature male Wistar rats reduced the fractional rate of protein synthesis (k(s), %/ day) in all regions (atria and ventricles) of the normal and overloade d (30 days aortic constricted) hearts. The responses in k(s) were vari able. In normal heart, the atrial tissues showed a slightly greater de crease in k(s) (approx. -30%) when compared to the ventricular regions (approx -20%). The most pronounced effects occurred in the hypertroph ied left ventricular tissues where the depressive effects of ethanol o n the rate of protein synthesis were potentiated in the presence of hy pertrophy (k(s) reduced by approx 40%). Other regions of the overloade d heart did not show additional sensitivity to the effects of ethanol on protein synthesis in the presence of chronic hypertension. In concl usion, the deleterious effects of ethanol on the left ventricle are ad ditive in the presence of chronic hypertrophy. These results may have important implications for other cardiac abnormalities where there is also concomitant ethanol exposure.