Role of inhibin in polycystic ovarian syndrome

The possible role of inhibin in the etiology of polycystic ovarian syndrome (PCO) was studied. In rats PCO was induced by thiouracil and human chorionic gonadotropin (hCG). These animals were grouped under different treatment schedules: inhibin; antibodies to inhibin; ovine follicle stimulating hormone (FSH). In rats treated with antibodies to inhibin, there was a decrease in ovarian weight concomitant with specific increase in serum FSH levels. No changes in serum luteinizing hormone (LH) and prolactin levels were observed. However, testosterone levels were significantly decreased. Histological examination of the ovaries showed a marked arrest in the cyst formation with new growing follicles. In animals treated with inhibin, testosterone levels increased without any accompanying changes in ovarian weight. The circulating levels of prolactin and LH were unaffected. A decrease in serum FSH levels was accompanied by an increase in the number of cysts. The study corroborates the hypothesis that inhibin is involved in the development of PCO syndrome. Hence, an antagonist to inhibin may prove useful for the treatment of women with this condition.