Sites of production of sex steroids: secretion of steroids from x-irradiated and polycystic ovaries of rats

Ovaries of immature rats and PMS-induced pregnant rats were unilaterally x-irradiated. Ten days later, the concentrations of pregnane compounds in the ovarian venous plasma were measured. LH (2 μg) was injected iv 30 min before bleeding. A comparison of steroid levels in the ovarian venous effluent of rats with and without destruction of selected tissue components by irradiation of the ovaries suggests that the follicles contribute to the secretion of 5α-pregnane-3,20-dione and 3α-hydroxy-5α-pregnan-20-one in the presence of interstitial gland tissue. Because it is known that follicular tissue is involved in the production of estrogens, we studied the interrelationship between the secretion of the two progesterone metabolites and estrogens in follicular polycystic ovaries of androgen-sterilized rats. Normal ovaries of diestrus-2 rats were used as controls for the polycystic ovaries. The injection of LH greatly increased the secretion of 5α-pregnane-3,20-dione and 3α-hydroxy-5α-pregnan-20-one within 1 h in normal ovaries, but the response of polycystic ovaries was low, suggesting low 5α-reductase activity in the cystic ovary. The polycystic ovaries exhibited a marked increase in the secretion of estrogens in response to LH, whereas normal ovaries showed no significant change. These results suggest that low 5α-reductase activity may be causally related to the high level of estrogen secretion in polycystic ovaries of androgen-sterilized rats