No effect of acute ethanol administration on hepatic protein synthesis and export in the rat in vivo.

Ethanol was administered as a single p.o. dose (2.88 g X kg-1) to male rats (220-265 g body weight) to give blood alcohol concentrations of 40-50 mM for the following 3 hr. Controls were given isoenergetic amounts of either sucrose or lipid. Liver protein synthetic rates were measured during a 20 min interval at the end of the 3 hr period following the administration of diets. Although ethanol caused a 32% reduction of the incorporation of labelled valine into liver protein compared to the sucrose group during the 20 min interval, no such reduction was found when the synthetic rate of stationary liver protein was calculated (182 vs. 214 (not significant) pmol X mg protein-1 X min-1) for same interval. There was no difference between the ethanol and lipid group with regard to either incorporation or synthetic rates. Incorporation of valine into plasma proteins was reduced in the ethanol group compared to the sucrose group, but not compared to the lipid control group, again demonstrating no ethanol-specific effect. When the incorporation into plasma proteins was divided by the specific radioactivity of valyl-tRNA at 20 min, the difference between the ethanol and the sucrose group disappeared. The fraction of newly synthesized proteins exported to the plasma measured 40 min after the injection of labeled valine, was equal in all three treatment groups. It was concluded that acute administration of ethanol has no consistent effect on liver protein synthesis and secretion in vivo.