The relationship between circulating andorgens, obesity, and hyperinsulinemia on serum insulin-like growth factor binding protein-1 in the polycystic ovarian syndrome

OBJECTIVE: Our purpose was to evaluate the relationship of obesity, hyperinsulinemia, and hyperandrogenemia on serum insulin-like growth factor binding protein-1 levles in women with the polycystic ovarian syndrome. STUDY DESIGN: Insulin-like growth factor binding protein-1, insulin, and androgen levels were studied during a 3-hour intravenous glucose tolerance test in 16 women with polycystic ovarian syndrome (nine obese and seven nonobese) and 20 healthy between basal (r = 0.77, P = 0.04) and area under curve (r = 0.86, p< 0.001) insulin-like growth factor binding protein-1 with basal androstenedione in the nonobese women with polycystic ovarian syndrome but not in other groups of women examined or between other androgens and insulin-like growth factor binding protein-1. An inverse relationship was observed between log area under curve insulin-like growth factor binding protein-1 levels and log body mass index in polycystic ovarian syndrome (r = −0.54, P = 0.03) and in normal women (r = −0.43, P = 0.06). The log area under curve insulin-like growth factor binding protein-1 level was approximately an inverse linear function of log area under curve insulin response for both women with polycystic ovarian syndrome (r = −0.70, p< 0.001) and control women (r = −0.72, p< 0.001). Additionally, after the area under curve insulin response during intravenous glucose tolerance testing was controlled for, the decline in area under curve insulin-like growth factor binding protein-1 responses was on average 66% less in both obese and nonobese women with polycystic ovarian syndrome compared with same-weight controls (95% confidence interval 110% to 270%, p = 0.04). CONCLUSION: These data indicate that insulin and body mass index are the major determinants of circulating insulin-like growth factor binding protein-1 and that chronic hyperandroenemia does not appear to further reduce serum insulin-like growth factor binding protein-1 levels in obese or normal-weight women with polycystic ovarian syndrome.