Effect of glucose on incorporation of l-lysine-U-C¹⁴ into testicular proteins

The incorporation of l-lysine-U-C 14 into proteins of slices of a number of tissues of the rat has been studied in the presence and absence of glucose under aerobic conditions. The addition of 0.009 m glucose increased the incorporation of radioactive lysine into proteins of slices of rat testis and head of epididymis by 600 and 160%, respectively. Similar additions of glucose caused essentially no change to a 50% enhancement of protein labeling in slices of thymus, spleen, pancreas, tail of epididymis, kidney, brain, diaphragm, heart, liver, seminal vesicle, a number of transplantable rat tumors, and regenerating rat liver. The data obtained indicate that the enzymatic systems involved in the incorporation of labeled lysine into protein of the testis are more sensitive to the addition of exogenous glucose than those of a number of other tissues of the rat.