Effect of retinol and retinoic acid on leucine l 14C incorporation into plasma and liver proteins in rats fed different levels of dietary protein
The effect of feeding 50,000 I.U. of retinol or 5 mg of retinoic acid for two days to rats fed casein at 20, 5 and 0% levels respectively for 2 wk was studied in liver and plasma protein, and the incorporation of leucine 1 14C in these proteins was determined. Neither retinol nor retinoic acid affected plasma protein content at any level of dietary protein fed. Retinol increased liver proteins in rats fed 5% protein and protein free diets, whereas retinoic acid affected this increase when there was no protein in the diet. Both retinol and retinoic acid increased the leucine 1 14C incorporation into plasma proteins of rats fed low protein and protein free diets. Both retinol and retinoic acid significantly increased the incorporation of leucine 1 14C into liver proteins of rats fed 20% casein whereas no such effect was seen in rats fed low protein and protein free diets. Retinoic acid inhibited the increased incorporation of leucine 1 14C observed in rats fed the low protein and protein free diets.
