In vitro inhibition of protein synthesis in rat liver as a consequence of ethanol metabolism

Ethanol depresses the incorporation of amino acids into cell proteins of rat liver slices. This inhibition is nearly concentration independent for alcohol concentrations between 3 and 150 mM, and disappears after removal of ethanol. The effect of ethanol on liver protein synthesis is lower in fasting than in fed rats. The inhibition of protein synthesis does not occur in guinea-pig kidney slices, a tissue virtually devoid of alcohol dehydrogenase, and is prevented in liver by pyrazol. Acetaldehyde brings about a concentration-dependent inhibition of protein synthesis both in rat liver and in guinea-pig kidney. Acetoin, up to 5 mM concentration, does not influence protein synthesis in liver. Sorbitol, which mimics ethanol as regards the shifting of the redox level in the hepatocyte, depresses protein synthesis in liver in relation to its concentration in the medium. Pyruvate partially removes the inhibition of cell protein synthesis induced by ethanol. The data show that the inhibition of cell protein synthesis in rat liver slices by ethanol is a consequence of alcohol metabolism. They also suggest that this inhibition is due to acetaldehyde as well as to the shifting of the redox level in the cell.