GONADOTROPIN RESPONSIVENESS TO ULTRALOW-DOSE LEUPROLIDE ACETATE ADMINISTRATION IN BABOONS

Objective: To evaluate the gonadotropin response to ultralow doses of a GnRH agonist, leuprolide acetate (LA). Design: Prospective and cross -controlled. Setting: Primate research center. Subjects: Four reproduc tive age cycling baboons (Papio cyanocephalus). Interventions: Three d ifferent doses of LA were given intravenously to each animal followed by serial sampling. Main Outcome Measures: Response patterns of circul ating serum gonadotropin levels. Results: All four animals responded t o each of the three doses of LA in a dose-dependent fashion. Levels of LH and FSH peaked at 49.5 +/- 2.6 mIU/mL and 72.5 +/- 3.4 mIU/mL, res pectively, for the highest dose studied (0.17 mug/kg). Levels of LH pe aked earlier but were lower than the FSH peak levels. Conclusions: Sup raphysiological levels of gonadotropins are attained after the adminis tration of ultralow doses of LA. The level of the response is dose-dep endent and is in the range that is required to attain controlled ovari an hyperstimulation.