Response of uterine glucose-6-phosphate dehydrogenase isoenzymes to estrogen.

To show that uterine glucose–6– phosphate dehydrogenase (G6PD) exists in multiple molecular species (isoenzymes), cytosols were subjected to polyacrylamide disc gel electrophoresis, stained specifically for G6PD and quantitated by planimetry of absorbancy tracings from spectrophotometric scanning of the gels. The uterus, 10 days after ovariectomy, contained 3 isoenzymes with the following SA (μmoles NADPH/ min/mg protein) : G6PD–1, 0.021; G6PD–2, 0.005 ; and G6PD–3, 0.0IS, in order of decreasing mobility. Estradiol benzoate, from 0.01 to 1000 μg/ day/animal for 4 days, produced a dose—related increase in total G6PD activity, primarily due to a 7–fold elevation in G6PD–1, a slight increase in G6PD–2 and a decrease in G6PD–3. Uterotrophic doses of testosterone and progesterone had no effect on G6PD activity or isoenzyme patterns at the doses used. A time—course study, using 100 (xg estradiol benzoate per day, showed the peak of G6PD–1 activity was obtained within 3–4 days. Concomitant administration of the ...