Effects of Chronic Ethanol Treatment on Rat Liver Mitochondrial Protein Synthesis

Chronic ethanol treatment of male Sprague-Dawley rats resulted in a 50% decrease in the rate of incorporation of precursor leucine into isolated mitochondria. This decrease is manifest in a decreased labeling of three polypeptides of inner mitochondrial membranes that are the major products of in vitro mitochondrial protein synthesis under the conditions employed. Immunoprecipitation of cytochrome-c oxidase revealed that these three polypeptides are subunits 1, 2, and 3 of cytochrome-c oxidase and have apparent molecular weights of 33,000, 25,000, and 20,000. Sixty percent of the total incorporated radioactivity is associated with these polypeptides. A decrease in the contents of subunit 2 and of a second polypeptide with an apparent molecular weight of 22,000 was also noted as an effect of chronic ethanol treatment.