Inhibition of protein degradation in regenerating rat liver by ethanol treatment

The effect of ethanol on the activity of ornithine decarboxylase (ODC), tyrosine aminotransferase (TAT), alanine aminotransferase (ALAT) and lactate dehydrogenase (LD), as well as on protein concentration, was studied in regenerating rat liver after partial hepatectomy. It was found that administration of an ethanol-containing liquid diet for 5 days after partial hepatectomy caused a significant accumulation of proteins in the liver. The activities of ODC and TAT were stimulated by ethanol treatment in the beginning of the regeneration. In control livers, partial hepatectomy decreased the activity of ALAT, but ethanol prevented this decrease. No differences in the activity of LD was found between ethanol and control groups after partial hepatectomy. When the half-lives of ODC and TAT were measured 24 hr after partial hepatectomy by using cycloheximide, it appeared that ethanol caused a significant stabilization of both enzymes. It is concluded that ethanol caused inhibition of degradation of ODC and TAT and it is suggested that this could be a general phenomenon, and could markedly contribute to the pathological accumulation of proteins in the liver after chronic ethanol consumption.