Inhibition of RNA and protein synthesis by ethanol in regenerating rat liver: evidence for transcriptional inhibition of protein synthesis.

The effect of ethanol on RNA and protein synthesis was studied in regenerating rat liver. Partial hepatectomy stimulated the activity of ornithine decaroxylase (ODC) and that of tyrosine aminotransferase (TAT) as well as the synthesis of RNA. The intubation of ethanol (3g/kg) 1 hr before the operation inhibited the stimulation of ODC and TAT when measured 4 hrs after the operation. Ethanol administration also inhibited RNA synthesis. By using inhibitors of alcohol dehydrogenase and aldehyde dehydrogenase it was shown that the inhibition of RNA synthesis (and also that of protein synthesis) was most probably a direct effect of ethanol itself. When RNA synthesis was measured in vivo in purified nuclei, ethanol inhibited the incorporation of nucleotides to RNA. It is suggested that ethanol inhibits protein synthesis in regenerating rat liver at the transcriptional level by interfering in nuclei with the synthesis of RNA.