Objective: To assess the impact of ovarian hormone deprivation on serum concentrations of GH and insulin-like growth factor I (IGF-I) in women with polycystic ovarian syndrome (PCOS). Design: Growth hormone and IGF-I levels were measured before, during, and at the end of a 6-month period of treatment with leuprolide acetate (LA) depot. Normal cycling and ovariectomized women served as controls. Setting: The Clinical Research Center of Northwestern University Medical School. Patients: Six women with PCOS, seven normal cycling women, and six ovariectomized women. Interventions: The PCOS and normal cycling subjects were treated with six consecutive monthly injections of LA depot 3.75 mg IM. Main Outcome Measures: Circulating concentrations of GH and IGF-I. Results: After 3 months of treatment, GH levels decreased modestly in the PCOS group; however, these changes were not significant. No further decline was observed at 6 months. Growth hormone levels were unaffected in the normal cycling group. Levels of IGF-I remained unchanged in both groups. Mean baseline levels of both GH and IGF-I in the ovariectomized group were lower than those of the normal cycling and PCOS groups at all time points, but not significantly so.