SERUM LEVELS OF INSULIN-LIKE GROWTH-FACTOR BINDING PROTEIN-1 AND OVULATORY RESPONSES TO CLOMIPHENE CITRATE IN WOMEN WITH POLYCYSTIC OVARIANDISEASE

Objective: To study the serum levels of insulin, insulin-like growth f actor I (IGF-I), and insulin-like growth factor binding protein-1 (IGF BP-1) in relation to clomiphene citrate (CC) responsiveness in women w ith polycystic ovarian disease (PCOD). Design: Prospective. Patients, setting: Twenty-three women with PCOD admitted consecutively to the Un iversity Infertility Clinic, a tertiary referral center. Interventions : Blood samples were taken at fasting state and during oral glucose to lerance test (OGTT) for the determination of insulin, IGF-I, and IGFBP -1. A dose of 50 to 200 mg/d CC was given for ovulation induction. Res ults: With CC treatment, ovulation was achieved in 13 of 23 PCOD patie nts. The IGFBP-1 concentration was lower in CC nonresponders than in C C responders (20.5 +/- 4.0 ng/mL versus 41.0 +/- 8.5 ng/mL) (P < 0.05) . This difference was accentuated in 13 lean PCOD patients. Lean CC no nresponders (n = 7) had almost threefold lower serum IGFBP-1 levels th an lean CC responders (n = 6) (24.0 +/- 3.1 ng/mL versus 61.8 +/- 8.6 ng/mL) (P < 0.01). By contrast, among 10 obese PCOD patients, the IGFB P-1 levels were low irrespective of CC responsiveness (14.8 +/- 8.0 ng /mL versus 16.7 +/- 7.2 ng/mL). The differences remained during OGTT. The concentrations of IGF-I, insulin, sex hormone-binding globulin, LH , FSH, and androgens showed no significant differences between CC resp onders and nonresponders. There was an inverse correlation between ser um insulin and IGFBP-1 levels in obese PCOD patients, whereas this was not seen in lean patients. Conclusion: In lean PCOD patients, low ser um IGFBP-1 concentration is related to CC unresponsiveness by a mechan ism unrelated to insulin.