抄録
Growing rats were fed a protein-free diet or a diet containing 25% casein for seven days. The rate of RNA synthesis in the liver was examined by determining the incorporation of 14C-orotic acid into CMP and UMP of liver acid-soluble fraction and RNA hydrolysate on the basis of relative specific radioactivity.
The rate of RNA synthesis was raised in the rats fed protein-free diet up to 170% of that with 25% casein diet. The rate of RNA synthesis was also measured when dietary components, such as casein, butter, and starch were individually given for three hours to rats which had been adapted, by training, to spaced feeding for three hours every day. The rate of RNA synthesis was raised in rats given casein, butter, and starch, up to 117%, 144%, and 146%, respectively, of that in rats fasted. From these results, it is presumed that the enhanced RNA synthesis in the livers of rats fed the protein-free diet may be due to the increased uptake of starch which was contained at 90% in the diet.
