Postnatal development of interstitial glands in rabbit ovaries, with particular reference to the ability of steroidogenesis

Using the ovaries of Japanese white rabbits 0 to 720 days after birth, the activities of different kinds of hydroxysteroid dehydrogenases (HSDs) were histochemically observed, and the steroid metabolism in interstitial glands was discussed. Primary and secondary interstitial glands first came to be seen at 60 and 90 days of age, respectively. The activities of delta5-3beta-HSD using DMA, pregnenolone and 17alpha-hydroxypregnenolone as the substrates, 17beta-HSD using estradiol-17beta and testosterone as the substrates, and 20beta-HSD using 17apha-hydroxyprogesterone and 20beta-hydroxyprogesterone as the substrates were weak in primary interstitial glands of 60-day-old rabbits. Such the activities were also observed in secondary interstitial glands of 90-day-old animals, but the activity of delta5-3beta-HSD using DHA as the substrate was increased to a high level. Secondary interstitial glands of 120- to 720-day-old animals showed the strong activities of delta5-3beta-HSD, 17beta-HSD and 20brta-HSD. On the other hand, the activity of 20apha-HSD using 20apha-hydroxyprogesterone as the substrate was not observed in both primary and secondary interstitial glands of animals of any ages. In addition, the activities of glucose-6-phosphate dehydrogenase, NADH2-dehydrogenase and NADPH2-dehydrogenase were always present at a high level in both primary and secondary interstitial glands of rabbits of all ages. These results suggest that both primary and secondary interstitial glands of rabbits have ability to metabolize progestin, such as progesterone, 17alpha-hydroxyprogesterone, 17apha, 20beta-hydroxyprogesterone and 20beta-hydroxyprogesterone, and estrogen and androgen but not 20alpha-hydroxyprogesterone, and that the ability of steroidogenesis is active in secondary interstitial glands of animals after 120 days of age.