Low levels of low molecular weight insulin-like growth factor-binding protein in patients with polycystic ovarian disease.

Insulin-like growth factors IGF-I and IGF-II are bound to specific binding proteins in serum. The lower mol. wt binding protein (IGF-BP) has been detected in various tissues, including secretory endometrium and preovulatory follicles of the ovary. This group studied the circulating levels of IGF-BP in the serum of 23 patients with polycystic ovarian disease (PCOD) and found that one-third of them have a subnormal level. In comparison with PCOD patients with a normal level, those with a subnormal level had a higher degree of obesity and a tendency to be more hirsute. They also had a higher serum insulin concentration and testosterone/sex hormone-binding globulin (SHBG) ratio, but lower serum SHBG concentration than those with a normal IGF-BP level. PCOD is the second abnormal clinical condition, after insulinoma, in which subnormal serum IGF-BP concentrations have been reported. The significance of low serum IGF-BP levels to pathophysiology of PCOD remains to be elucidated by studies on local interaction between IGF-BP and insulin in the polycystic ovary.