THE INFLUENCE OF CERTAIN STEROIDS ON THE OXIDATION OF ALPHA-KETO ACIDS1

Abstract

The synthesis of citrate from pyruvate and fumarate by rat liver homogenates was inhibited in vitro by testosterone, desoxycorti-costerone, ethinyl estradiol, progesterone and diethylstilbestrol. Other steroids which were relatively ineffective as inhibitors of citrate synthesis in vitro were estradiol, estrone, pregnenolone, methyl androstenediol, methyl androstanediol, cortisone, cholesterol and ouabain. The synthesis of acetoacetate from pyruvate was markedly inhibited by testosterone, desoxycorticosterone, progesterone and diethylstilbestrol. Those steroids which inhibited the synthesis of citrate and acetoacetate also inhibited the oxidation of alpha-ketoglutarate in vitro. The oxidation of succinate was not inhibited in vitro by those steroids which inhibited the oxidation of alpha-ketoglutarate and the synthesis of citrate and acetoacetate.