Effect of level of dietary protein on the distribution of 14C-activity from exogenous 14C-inosine in chicks

The effect of dietary protein level on the metabolic fate of intraperitoneally administered (exogeneous) 8-14C-inosine in chicks was studied. Three different protein level diets (low, standard and high) were prepared. Chicks were fed on these diets for 10 days, respectively and the following results were found: (1) RNA content of liver, small intestine and muscle in chicks fed on a low protein diet was decreased as compared to other diet groups, but no difference was observed in kidney or pancreas. (2) 14C uptake by organs from exogeneous 8-14C-inosine was determined. The uptake of 14C in kidney, pancreas and small intestine was higher than that in liver and muscle. Moreover, the uptake by tissues in the low protein groups was significantly higher than that in either the standard or high protein groups, but no difference was observed between these latter two groups. (3) The rate of incorporation of 14C labelled purine by acid soluble materials and RNA was higher in kidney, pancreas and small intestine than in liver and muscle, and also higher in chicks fed on a low protein diet than in either the standard or high protein groups. (4) It was revealed that the 14C-labelled purine rings from 8-14C-inosine were incorporated into AMP and GMP as constituents of RNA. (author)