The influence of energy intake on ribonucleic acid metabolism

Abstract

When the basal (sub. maintenance) diet fed to rats contained protein, addition of energy in the form of either carbohydrate or fat resulted in a considerable increase in total ribonucleic acid (RNA) per liver, but when the diet lacked protein, an increase in energy intake caused only minimal changes. Uptake of P32 by RNA, as measured by relative specific activity, was unaffected by variations in energy intake when the diet contained protein, but it was considerably stimulated by addition of energy to the protein-free diet. These results indicate that the absolute rate of incorporation of P into RNA is dependent on energy intake. At each level of protein intake, the total number of P atoms incorporated into RNA is increased by raising energy intake, in one case by an increase in the total RNA per liver without a change in % of P atoms incorporated in a given time, in the other case by an increase in % incorporation rate accompanied by a smaller change in total RNA per liver.