Effect of starvation of the distribution of free and membrane-bound ribosomes in rat liver and on the content of phospholipid and glycogen in purified ribosomes.

The distribution of free and membrane-bound ribosomes in liver in response to starvation has not been clearly defined. An investigation has been made of the effects of starvation on the content of DNA, RNA, protein, phospholipid and glycogen in rat liver, on the distribution of free and membrane-bound ribosomes, and on the content of phospholipid and glycogen in free and bound ribosome fractions. The results indicate that starvation can produce up to a 50% reduction in hepatic ribosomes without altering either the fraction of rRNA relative to the total RNA or the distribution of free and membrane-bound ribosomes. In addition, the degree of contamination of isolated ribosomes with membranous material does not fluctuate with changes in the nutritional status of the animal. The results suggest that the relative capacities for protein synthesis among the two ribosome compartments are maintained during the early stages of starvation. Further, co-sedimentation with glycogen is not responsible for the presence of membranous materials in purified ribosomes.