Effects of ethanol, nutritional status, and composition of the incubation medium on protein synthesis in isolated rat liver parenchymal cells

Protein synthesis, measured as the incorporation of [ 14C]valine into cell proteins and into proteins secreted into the medium, and albumin production were studied in isolated rat liver hepatocytes. Protein synthesis was substantially higher in cells from fed rats than in cells from fasted rats. Addition of carbohydrates or amino acids increased protein synthesis in cells from fasted rats, whereas no effect was seen in cells from fed rats. Addition of oleate had no effect on protein synthesis. Ethanol inhibited protein synthesis in cells from fasted rats, whereas no or only small effect was seen in cells from fed rats. Simultaneous addition of carbohydrates diminished the inhibitory effect of ethanol, whereas addition of oleate increased the inhibitory effect of ethanol. It is suggested that the rate of protein synthesis in cells from fasted rats could be restricted by lack of precursors for synthesis of nonessential amino acids. The effect of ethanol is explained by an inhibition of gluconeogenesis.