RESPONSES OF SERUM GONADOTROPHINS TO LH-RELEASING HORMONE AND OESTROGENS IN JAPANESE WOMEN WITH POLYCYSTIC OVARIES

Abstract

In order to define the abnormality in gonadotropin secretion in Japanese women with polycystic ovaries (PCO) who rarely show virilization and markedly enlarged ovaries, basal levels of LH [luteinizing hormone] and FSH [follicle stimulating hormone], and responses of serum gonadotropins to LH-releasing hormone (LH-RH) or estrogens were determined by radioimmunoassay. Eleven patients with PCO diagnosed by laparotomy or laparoscopy and 30 normal women in the follicular phase were studied. The mean (.+-. SD) basal level of LH was significantly higher in patients with PCO than in normal controls (PCO 28.6 .+-. 2.4 vs. in normal 10.9 .+-. 3.0 mIU/ml), while the mean FSH level in PCO patients was not significantly different from that in the normal controls (9.7 .+-. 0.7 vs. 11.4 .+-. 2.6 mIU/ml). The mean LH/FSH ratio in PCO patients was significantly higher than that in normal controls (3.2 .+-. 0.9 vs. 1.0 .+-. 0.3). Exaggerated response of LH to LH-RH was observed in PCO patients, while the FSH response was comparable with the normal controls. Ten out of 11 patients with PCO showed LH release exceeding the basal level after bolus i.v. injection of 20 mg conjugated estrogens (Premarin), and virtually the same mean net increase in LH from the basal level was obtained in both PCO patients and normal controls. Since the abnormalities in gonadotropin secretion in Japanese women with PCO are not different from those reported in patients with PCO in Europe and USA, it seems likely that lower incidence of markedly enlarged ovaries and virilization in Japanese patients may be caused by the difference in ovarian response to gonadotropin.