The relationship between circulating androgens, 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 levels 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 control women (10 obese and 10 nonobese).

RESULTS

Positive correlations were observed 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 hyperandrogenemia 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.