Serum Müllerian-inhibiting substance levels in adolescent girls with normal menstrual cycles or with polycystic ovary syndrome.

OBJECTIVE: To compare serum müllerian-inhibiting substance (MIS) concentrations in adolescent girls with polycystic ovary syndrome (PCOS) or normal menstrual cycles. DESIGN: Prospective study. SETTING: University department of obstetrics and gynecology. PATIENT(S): Thirty-one girls (12-18 years old) with PCOS and 17 girls (12-19 years old) with normal menstrual cycles. INTERVENTION(S): Serum was collected from girls with PCOS or normal cycles during the early follicular phase of the menstrual cycle, stored frozen until assayed. MAIN OUTCOME MEASURE(S): Serum levels of MIS, E2, free-T, androstenedione, LH, and FSH. RESULT(S): Serum MIS levels in girls with PCOS were significantly higher compared with normal girls (4.1 +/- 2.2 [SD] and 2.4 +/- 1.0 ng/mL, respectively). The subjects were stratified for body mass index (BMI) (< and >25 kg/m2). Serum MIS levels in PCOS girls (4.2 +/- 3.0 ng/mL [BMI <25 kg/m2] and 4.0 +/- 1.6 [BMI >25 kg/m2]) were significantly higher compared with normal girls (2.2 +/- 0.8 and 2.6 +/- 0.7 ng/mL, respectively). CONCLUSION(S): Adolescent girls with PCOS have significantly higher serum MIS levels compared with normally cycling girls. Serum MIS levels in PCOS were not influenced by BMI. Increased MIS production may represent an early manifestation of the disease.