Leuprolide acetate lowers circulating bioactive luteinizing hormone and testosterone concentrations during ovarian stimulation for oocyte retrieval.

Levels of immunoreactive luteinizing hormone (LH), bioactive LH, and testosterone (T) were determined in 52 women receiving human menopausal gonadotropins (hMG). In 26 women receiving leuprolide acetate (LA) preceding hMG, there was a significant suppression of immunoreactive LH and bioactive LH. The characteristic increase in serum levels of bioactive LH and T were absent. Follicular fluid estradiol and T concentrations, and serum progesterone were not different. The lower circulating levels of T may reflect reduced LH-stimulated androgen accumulation in smaller nonaspirated follicles and may account for the enhanced follicle recruitment observed during LA. The lack of premature luteinization despite marked rises of bioactive LH in the absence of LA is consistent with normal events during the menstrual cycle and was due to the early termination of hMG stimulation.