The response of the growth hormone and insulin-like growth factor I axis to medical castration in women with polycystic ovarian syndrome

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. Conclusions: Medical castration fails to significantly alter serum GH and IGF-I levels in either normal cycling or women with PCOS. These data indicate that GH secretion is not modulated by hormones of ovarian origin in either group, at least over the period of time studied.