Phosphate Metabolism in Nutritional Muscular Dystrophy and Hyperthyroidism. ∗

Abstract

Summary

1) Rabbits and rats were made Vit. E-deficient by feeding a purified diet. Control animals received the same diet supplemented with Vit. E. Hyperthyroidism was induced in rats by giving subcutaneous injections of sodium thyroxinate. Control and experimental animals from each group were injected with P³² in dilute HCl and specific activities of plasma inorganic phosphate, and skeletal muscle inorganic phosphate, creatine phosphate, and ATP phosphate determined. The S. A. of the plasma inorganic phosphate was unchanged by Vit. E deficiency and was decreased by hyperthyroidism. Skeletal muscle inorganic phosphate S. A. was increased by Vit. E deficiency and the difficulties in interpreting these data were discussed. The S. A. of phosphates of creatine phosphate and ATP phosphate were high in both Vit. E deficient rabbits and hyperthyroid rats. The significance of these findings was discussed in relation to turnover of creatine phosphate and ATP. 2) These experiments indicate that there is an elevated turnover of skeletal muscle intracellular inorganic phosphate and a normal or decreased turnover of skeletal muscle creatine phosphate and ATP in Vit. E deficiency. In contrast there appears to be no depression in turnover of creatine phosphate and ATP in hyperthyroid rats.