Creatine metabolism in vitamin E deficiency in the rat

Abstract

Creatine-2-C14 was injected intraperitoneally into normal, vitamin E-deficient, and previously deficient rats treated with α-tocopheryl acetate. Creatine was isolated after various time intervals from different skeletal muscles, heart, brain, kidney, liver, blood serum, erythrocytes, retroperitoneal fat, urine, and total residual carcass, and its specific activity and quantity determined. Creatinine was isolated from urine and assayed for radioactivity. An increase in the ratio of specific activities of "free" creatine to muscle creatine was observed in vitamin E-deficient rats. After treatment with α-tocopheryl acetate, this ratio returned to normal values. From plots of specific activity vs. time, turnover times for creatine were computed: total carcass, 56 days; skeletal muscle, 51–53 days. Turnover time of creatine in carcass, brain, and skeletal muscle, with the exception of pectoralis muscle, was identical in normal and vitamin E-deficient rats. Specific activity in pools of free creatine of vitamin E-deficient rats initially was higher but subsequently became lower than that of normal rats. We concluded that uptake of creatine by muscle is diminished in vitamin E-deficient rats and as a consequence the size of the free creatine pool increases and creatinuria results.