Body weight, hyperinsulinemia, and gonadotropin levels in the polycystic ovarian syndrome: evidence of two distinct populations.

OBJECTIVE: To investigate the impact of body weight (BW) and insulin levels on gonadotropin and androgen levels in women with the polycystic ovarian syndrome (PCOS). DESIGN: Comparative study of endocrinologic parameters in PCOS women. SETTING: University Hospital Reproductive Endocrinology Unit. PATIENTS: Thirty obese and 19 nonobese women with PCOS. Seven obese and 7 nonobese normal women. MAIN OUTCOME MEASURES: Serum concentrations of insulin, testosterone, androstenedione, luteinizing hormone (LH), follicle-stimulating hormone. Serum LH response to gonadotropin-releasing hormone (GnRH) administration and assessment of insulin resistance by the continuous infusion of glucose with model assessment (CIGMA) test. RESULTS: Fasting insulin levels correlated with body mass index (BMI). Basal LH levels correlated inversely with BMI. Nonobese women with PCOS had a higher LH response to GnRH than obese women with PCOS. Only obese women with PCOS showed insulin resistance and fasting hyperinsulinemia. CONCLUSIONS: The data suggest that women with PCOS may be divided into two subgroups: those with obesity, insulin resistance, hyperinsulinemia, and normal/minimally elevated LH levels and those with normal BW, elevated LH levels, and normoinsulinemia.