[Influence of different quantities of dietary protein on the relationship between age and utilization of glycine radiocarbon in the synthesis of lipids and glycogen].

Incorporation of the transformation products of 2-14C-glycin into liver glycogen and liver tissue lipids, as well as those of the kidneys, heart and skeletal muscles of young and old rats (3 and 24 months) kept on isocaloric food rations with 9, 18 and 36% of caseine was studied. The glycogen and lipids content, as well as the level of their specific radioactivity were shown to depend on the composition of the food ration, the animals age and on the kind of the tissue examined. The specific radioactivity of the liver lipids with restricted protein consumption is higher in young animals, and with an elevated intake thereof in the old ones. The glycogen radioactivity is greatest in animals of both age groups fed on a ration with an optimal protein content. An increased proportion of protein in rations of old animals is attended by a more intensive utilization of its metabolites in the lipids exchange.