Activity of ovarian delta 5-3 beta-hydroxysteroid dehydrogenase in the domestic fowl (Gallus domesticus) with respect to age.

The distribution of delta 5-3 beta-hydroxysteroid dehydrogenase was examined in the ovaries of hens aged 8--30 weeks. At all ages the interstitial cells (both thecal and stromal) gave a positive formazan reaction, but a positive reaction was not obtained in the granulosa cells of follicles less than 5 mm diameter in mature or immature birds. Since activity was restricted to follicles of larger size than this, it is concluded that steroidogenesis occurs in the granulosa cells for only the last 7--8 days of their life in the preovulatory follicle.