PENTOSE PHOSPHATE PATHWAY AND STEROIDOGENESIS IN THE IMMATURE RAT OVARY AFTER MALONATE TREATMENT

Abstract

ABSTRACT Suppression of succinic dehydrogenase (SDH) activity resulted in stimulation of glucose-6-phosphate dehydrogenase (G-6-PD) and Δ5-3β-hydroxysteroid dehydrogenase (Δ5-3β-OHD) activities in the immature rat ovary after malonate treatment. The same treatment also produced depletion in the ovarian ascorbic acid and elevation in cholesterol concentrations, together with increase in the ovarian and uterine weight. The results indicate that stimulation of ovarian steroidogenesis, resulting from accelerated pentose phosphate pathway in combination with increased concentration of cholesterol in the gland, is possibly due to a direct effect of malonate on the immature rat ovary. The rise in ovarian and uterine weights is not due to the decreased inactivation of oestrogen in the liver, but rather to stimulation of steroid hormone synthesis in the immature ovary following malonate administration.