Plasma levels of insulin-like growth factor-I and its binding protein in polycystic ovary syndrome.

ABSTRACT

Patients with polycystic ovary syndrome (PCOS) had significantly higher levels of total insulin-like growth factor (IGF-I) than those in age- and weight-matched controls (PCOS, 230 +/- 21 ng/ml; control, 180 +/- 16 ng/ml; mean +/- SE, p less than 0.05) as well as free IGF-I (PCOS, 3.8 +/- 0.2 ng/ml; control, 3.0 +/- 0.2 ng/ml; p less than 0.05). These elevated levels of IGF-I were correlated slightly with levels of LH and LH/FSH ratio (r = 0.171, p less than 0.05 and r = 0.239, p less than 0.01, respectively). Elevated fasting levels of insulin and decreased levels of IGF binding protein (32K-BP) were also observed in PCOS, and the levels of 32K-BP in PCOS were negatively correlated with insulin (r = -0.39, p less than 0.01). These results suggest that elevated IGF-I levels and decreased 32K-BP levels in the circulation are one of the endocrinological features of PCOS and that insulin is responsible for the clinical manifestation of decreased 32K-BP levels in PCOS.