Induction of LH surge with estradiol benzoate and its clinical significance in anovulatory women.

In order to investigate the hypothalamic function of anovulatory women serial determinations of the serum gonadotropins (LH and FSH) were made over a period of 120 h following the intramuscular injection of 1 mg of estradiol benzoate (E.B.). Ten women with normal menstrual cycles and 57 anovulatory women were subjected to this study. The positive release of LH in serum (exceeding at least 150% of basal level) in response to E.B. was noted in follicular phase of the cycles, but not in luteal phase, and in 31 of 57 patients the release came between 48 to 96 h after the E.B. injection. The LH surge after E.B. injection was difficult to provoke when the basal serum LH and estradiol (E2) levels were low: less than 10 mIU/ml and 50 pg/ml, respectively. Thirteen of 27 patients, who showed LH surge, ovulated because of Clomid. Only three of 17 patients, who did not show LH surge, ovulated as a response to Clomid. Ten of 14 patients, who showed LH surge after E.B. but did not ovulate after Clomid, revealed a polycystic ovarian disease (PCO), and the responsiveness to both E.B. and Clomid improved after wedge-resection of the ovaries. These results suggest that the serum E2 level is closely correlated to the ability for LH-RH production in the hypothalamic "surge center," and that the E.B. provocation test is useful for investigating the hypothalamic function of anovulatory women and for diagnosing preoperatively the PCO resistant to Clomid treatment.