Effects of Estradiol and Nicotinamide Adenine Dinucleotide Phosphate on the Rate of Synthesis of Uterine Glucose 6-Phosphate Dehydrogenase

Abstract

Abstract The levels of uterine glucose-6-P dehydrogenase (d-glucose 6-phosphate: NADP+ oxidoreductase, EC 1.1.1.49) in the ovariectomized mature rat are increased in response to intravenous administration of estradiol or intrauterine administration of NADP+. A highly specific rabbit antibody to this enzyme was prepared using purified rat liver glucose-6-P dehydrogenase as an antigen. Immunochemical titration of uterine glucose-6-P dehydrogenase from control and 24-hour estradiol- and NADP+-treated rats indicates that the ratio of enzyme activity to immunologically identifiable enzyme protein is unchanged by the in vivo treatments. The rate of incorporation of 14C-amino acids given by the intrauterine route into the uterine glucose-6-P dehydrogenase enzyme protein (isolated by immunoprecipitation with anti-body followed by sodium dodecyl sulfate polyacrylamide gel electrophoresis of the immunoprecipitate) is linear for 4 hours in uteri from control and 12-hour estradiol-treated rats. The rate of uterine glucose-6-P dehydrogenase synthesis begins to increase after an initial lag of 4 to 8 hours after administration of estradiol and is increased 18-fold above the controls during the interval from 12 to 16 hours after the hormone treatment. The rate of synthesis begins to decrease after 20 hours and approaches the rate seen in controls by 72 hours after injection of the steroid. NADP+ treatment does not increase the rate of enzyme synthesis during the first 16 hours during which time the amount of enzyme in the uterine cytosol is increased 2-fold.