Inhibin A & B levels according to the Ovarian Responses to Clomiphene Citrate in Women with PCOS

Roh, J S; Ji, I W; Jeong, E H; Kim, H J

Abstract

Clomiphene citrate (CC) has been extensively used for ovulation induction in anovulatory women with polycystic ovary syndrome (PCOS). Ovulation can be induced with CC in 75~85 % among them, but the reason for the failure to ovulate is not clear. Therefore, we studied relationship between serum levels of inhibin A, B and gonadotropin, and CC responsiveness in women with PCOS. We prospectively analysed twenty-four patients with PCOS. The diagnosis of PCOS was based on clinical symptoms (infetility, oligo-amenorrhea), laboratory findings (LH>5.8 mIU/mL or LH/FSH>1.2) and typical appearance of the ovaries by transvaginal sonography (TVS). The cut-off vaule of LH or LH/FSH ratio was determined by mean+2SD of twelve control women with regular menstrual cycle and normal ovarian morphology. Basal serum levels of inhibin A and B, LH, FSH, estradiol, testosterone, prolactin and TSH were measured on the 3rd and 10th day of the cycle. Ovulation was induced with 100 mg/day CC, from the 5th to 9th day of the cycle. The response was considered ovulatory when a few preovulatory follicle was found by TVS, followed by a normal rise of serum progesterone level (> or = 10ng/mL) in midluteal phase (n=15). If no ovulation was found, the patient was considered CC nonresponsive (n=9). There was no significant differences in basal hormonal profiles except the inhibin B/LH ratio between two groups. The LH/FSH ratio in the nonresponder and the inhibin B/LH ratio in the responder were significantly higher on the 10th day of the cycle. There was higher negative correlation between the basal inhibin B/LH ratio and FSH levels in the responder, but not in the nonresponder. Also, there was higher positive correlation between the inhibin B/LH ratio and estradiol on MCD 10 in the responder, but not in the nonresponder. In this study, higher basal inhibin B/LH ratio and the lack of correlation between the inhibin B/LH ratio and the levels of FSH or estradiol were associated with the lack of CC response in PCOS. Therefore, the CC nonresponder might be related to the disturbance of feedback mechanism between the pituitary and ovarian inhibin.