Combined Effects of Ethanol and pH-Change on Protein Synthesis in Isolated Rat Hepatocytes

Abstract: Rat liver parenchymal cells were isolated and incubated for 80 min. in buffered salt solutions. ¹⁴C-valine incorporation in the presence of a high concentration of unlabelled valine (4.2 mM) was taken as a measure of protein synthesis. The pH dependence of the synthesis of cell and medium proteins was studied at pH values varying from 6.6 to 7.9. The results showed that maximum protein synthesis occurred close to the physiological pH value. Protein synthesis was reduced at both lower and higher pH-values. Protein synthesis was inhibited by the addition of ethanol (30 mM). The relative inhibition caused by ethanol got more pronounced as the pH of the hepatocyte suspensions was lowered. The metabolism of ethanol resulted in lowering of the pH in cell suspensions. It is suggested that the depression of protein synthesis by ethanol could be mediated by the fall in pH due to ethanol metabolism.