DEHYDROGENASES IN THE PREPUBERTAL RAT OVARY: A HISTOCHEMICAL STUDY OF Δ5-3β-HYDROXYSTEROID DEHYDROGENASE AND ENZYMES OF CARBOHYDRATE OXIDATION FOLLOWING OXYTHIAMINE TREATMENT

Abstract

ABSTRACT A histochemical study of the NAD- and NADP-linked dehydrogenases, Δ5-3β-hydroxysteroid dehydrogenase (Δ5-3β-ODH) and glucose-6-phosphate dehydrogenase (G-6-PD), and the corresponding tetrazolium reductases in prepubertal rat ovaries following the administration of oxythiamine HCl revealed diminution in the activities of the two dehydrogenases, while the NAD- and NADP-tetrazolium reductase activities remained unchanged. The same treatment resulted in stimulation of dihydrolipoic dehydrogenase (DLDH) and succinic dehydrogenase (SDH) activities in the ovarian tissues. Supplementary histochemical demonstration of Δ5-3β-OHD activity in phosphate buffer at pH 9.0 revealed a similar localization of the enzyme as that observed at pH 7.1 and which was free of the NAD-linked diaphorase activity. A diminution of this ovarian enzyme activity at this pH was also evident, following oxythiamine treatment. The results indicate a suppression of ovarian steroidogenesis in the prepubertal rats as a result of an alteration of the pentose phosphate pathway enzyme, G-6-PD, following treatment with oxythiamine HCl.