Effect of danazol on estradiol-17beta and progesterone secretion by porcine ovarian cells in vitro.

The effect of danazol on progesterone (P4) and estradiol-17 beta (E2) secretion by cultured porcine granulosa cells was studied. Danazol markedly inhibited both basal and luteinizing hormone (LH)-stimulated P4 secretion by both granulosa and luteal cells in a dose-dependent manner during 24 hour culture periods. E2 secretion by granulosa cells was low (less than 3 ng/mg of protein) when cultured in the absence of an exogenous aromatizable substrate but was markedly increased when testosterone (T) was added to the media. Danazol inhibited E2 secretion by granulosa cells only when cultured in the presence of testosterone. E2 secretion by luteal cells was low even in the presence of testosterone and was not affected by danazol. These findings support the hypothesis that danazol can directly inhibit ovarian steroidogenesis independently of its inhibitory action on gonadotropin secretion.