Histochemical studies of 3 beta- and 20alpha-hydroxysteroiddehydrogenase in the adrenals and ovaries of the nu/nu mouse.

Adrenal glands and ovaries of nu/+ and nu/nu female mice were examined histochemically throughout the postnatal life for changes in distribution, intensity and appearance of activities of 3 steroid-converting enzymes. While the 3beta-OH-steroid- and pregnenolone-dehydrogenase did not reveal any difference, the 20alpha-hydroxysteroid-dehydrogenase (20alpha-OH SDH) showed a constant behaviour: the onset of the enzyme activity was detectable in the adrenals of nu/+ mice after the second week of age, in nu/nu mice 3--4 weeks later. The localization of 20alpha-OH-SDH was strictly confined to the zone of small cells, a zone lying between the x-zone and the zona fasciculata. In nu/+ mice, after reached sexual maturity at about 6--8 weeks of age, the enzyme progressively disappeared from the adrenals and simultaneously appeared in the ovaries. In nu/+nu mice, which had been kept separated from mating animals, the 20alpha-OH SDH persisted in adrenals even in adult stages. After pregnancy, both--nu/nu and nu/+, showed 20alpha-OH SDH-activity in ovaries and none in adrenals. In both, the enzyme was localized in involuting corpora lutea, whilst in nu/nu it was also present in the intersitial cells. This study indicates no disturbance in the formation of progesterone, but the process of its degradation, as indicated by 20alpha-OH SDH-activity, is definitely different in nu/+ and nu/nu.