Catechol oestradiol control of FSH-stimulated granulosa cell steroidogenesis

Catechol oestrogens are formed in the ovary but it is not known if they have a local function. Working with primary granulosa cell cultures prepared from immature rat ovaries, we found that the presence of 2-hydroxyoestradiol in the culture medium (48 h incubation) dramatically enhanced the steroidogenic response (progesterone production) to human FSH (100 ng/ml). The effect of 2-hydroxyoestradiol was dose-dependent and maximal (approximately 40 times the response to FSH alone) at 3.0 microM. The stimulatory action of 1.0 microM 2-hydroxyoestradiol was greater than 10 times more than that of 1.0 microM oestradiol but only half that of 1.0 microM testosterone; other catechol oestrogens (2-hydroxyoestrone, 4-hydroxyoestradiol, 2-methoxyoestradiol and 2-methoxyoestrone) were not stimulatory. The stimulatory actions of 2-hydroxyoestradiol and testosterone were partially additive and each was antagonized in the same way by the presence of a specific antiandrogen (SCH16423). These observations suggest a role for intrafollicular catechol oestradiol in modulating FSH-stimulated granulosa cell steroidogenesis; its mechanism of action may be similar to that of testosterone.