Differential effect of ethanol ingestion on the protein synthetic activities of free and membrane-bound ribosomes from liver of the weanling rat.

The influence of chronic ethanol ingestion on the protein synthetic activities of free and membrane-bound ribosomes was studied in vitro in the liver of young rat. Ethanol administration caused about 120% increase in the amino acid incorporative activity of free ribosomes. In contrast, membrane-bound ribosomes from the livers of ethanol-fed animals exhibited a 25% decline in their protein synthetic activity. This decline in the activity of membrane-bound ribosomes was abolished after dissolution of membranes by Triton X-100. Evidence was obtained suggesting that the observed alterations in protein synthesis due to ethanol intake are attributable to changes in pH5 enzyme fraction, altered amount of ribosome-associated mRNA and a damage to the endoplasmic reticulum membranes.