ESTRADIOL INDUCTION OF PYRUVATE KINASE IN RAT UTERUS

Estradiol-17β administered to ovariectomized rats increased the activity of uterine pyruvate kinase, while phosphopyruvate hydratase and phosphoglyceromutase remained unchanged. The effect of the hormone was inhibited by actinomycin D, 5-fluorouracil and cycloheximide. The increase in uterine pyruvate kinase was also partially blocked by the administration of progesterone to estradiol-treated rats. Uterine enzyme activity showed a cyclical variation in the normal animal and had the highest value at estrous. The behavior of hexokinase during the estrous cycle in the uterus of normal rats and after a chronic estradiol treatment was found to be similar to that of pyruvate kinase. However, the response of hexokinase activity to the hormone was much less marked than that of pyruvate kinase. The physiological significances of these findings are discussed. © 1968.