The effect of level of energy intake on the metabolism of ribonucleic acid and phospholipin in different parts of the liver cell

Abstract

1. 1. Rats receiving protein-free diets of differing energy content were killed at various time-intervals after injection with 32P. The livers were then separated into nuclear, mitochondrial, microsomal and cell sap fractions. An increase in the level of energy intake eventually caused a greater incorporation of 32P into the ribonucleic acid of all fractions, but the effect was less marked in the case of the cell sap. The uptake of 32P by the phospholipins was not increased in any cell fraction. 2. 2. Studies of the amount of ribonucleic acid, protein and phospholipin in different fractions of the liver cell cytoplasm were made in relation to the amount of protein and energy in the diet. Only the microsome fraction showed definite changes in the amount of ribonucleic acid when protein was withdrawn from the diet. The quantitative changes found in the ribonucleic acid of different cell fractions are discussed in relation to the rate of 32P incorporation.