Effect of exogenous hormones on the activity of delta 5,3 beta-hydroxysteroid dehydrogenase in cultured granulosa cells from proestrus and preovulatory rat ovarian follicles.

Activity of delta 5,3 beta-hydroxysteroid dehydrogenase (delta 5,3 beta-OH SD) in cultured granulosa cells isolated from rat ovarian follicles at various hours of proestrus was histochemically investigated. Control cultures as well as cultures with addition of luteinizing hormone (LH), follicle stimulating hormone (FSH), prolactin, and estradiol were carried on. In control cultures activity of the enzyme followed more or less the pattern observed in vivo. Exogenous LH added during preovulatory LH surge showed additive effect on enzyme activity. Other hormones stimulated enzyme activity on the morning of proestrus and at the time close to ovulation, when prolactin exerted most stimulatory effect.