| Abstract: | Steroid production and histological features of ovaries were compared either among normal +/+ mice of 3-12 days of age or among 12-day old mutant mice with various degrees of oocyte depletion. Whole ovaries were cultured in the medium containing 3H]progesterone and hCG or 4-androstene-3,17-dione and FSH; amounts of 3H]androgens or oestrogens released from the ovaries were assayed. FSH-responsive aromatase activity was detectable in ovaries of +/+ mice on day 3 after birth (2.6 +/- 0.4 pmol/2 ovaries/48 h), but the activity producing androgens from progesterone, under stimulation of hCG, was not detectable even on day 6 after birth (less than 0.1 pmol/2 ovaries/48 h). The androgen-producing activity appeared on day 9 after birth (1.16 +/- 0.25 pmol/2 ovaries/48 h), when follicles with more than two layers of granulosa cells developed. The ovaries of 12-day old Sl/Slt mice contained a considerable number of follicles with a single layer of granulosa cells, but did not contain any follicles with more than two layers of granulosa cells. The ovaries of Sl/Slt mice possessed aromatase activity (3.3 +/- 0.4 pmol/2 ovaries/48 h) but, not androgen-producing activity (less than 0.1 pmol/2 ovaries/48 h). The present results suggest that development of follicles with more than two layers of granulosa cells may induce the activity producing androgens from progesterone under stimulation of LH in suckling mouse ovaries, though the FSH-responsive aromatase activity is present even in follicles with a single layer of granulosa cells. |
