Estradiol activation of uterine reduced diphosphopyridine nucleotide oxidase.

Previous studies from this laboratory have shown that rat uterine homogenates contain a reduced pyridme nucleotide oxidase which is activated by ‘2,4-dichlorophenol and other phenolic substances (1, 2). Oophorectomy reduces the activity of this enzyme system to negligible levels but prompt restoration of the oxidative rate was observed upon the administration of small amounts of estradiol to the oophorectomized animals (3). Dichlorophenol had the greatest catalytic effect of any of the phenolic cofactors studied in this system. Under the optimum conditions for this catalysis it was not possible to replace the dichlorophenol with estradiol. When uterine homogenates were prepared from animals which had received large doses of estrogen, conditions were found for co-factor activity in vitro of estradiol-17P for the aerobic oxidation of reduced pyridine nucleotides. The present report is concerned with this stimulation in vitro by estradiol or other phenols of an oxidative system apparently induced by the administration of estrogen.