Hyperinsulinemia in polycystic ovary syndrome: relationship to clinical and hormonal factors

We analyzed the association between hyperandrogenism and hyperinsulinemia, and their relationship to body mass index, in a large series of patients with polycystic ovary syndrome (PCOS). A characteristic hormonal profile was sought in women with marked hyperinsulinemia. The patient group consisted of 73 women with PCOS, ranging in age from 16 to 29 years. The control group consisted of 34 healthy women with no evidence of hyperandrogenism, aged 19–30 years. None of the patients or control women had a body mass index above 27 kg/m². Follicle-stimulating hormone, luteinizing hormone, prolactin, testosterone, estradiol, androstenedione, dehydroepiandrosterone sulfate, sex hormone binding globulin, 17-hydroxyprogesterone, and free cortisol were determined by radioimmunoassay. The free testosterone index was calculated. The oral glucose tolerance test was used to analyze basal insulinemia, maximum insulin peak, and the insulinemia/glycemia index. In the group with PCOS body mass index was greater, free testosterone index was higher, and levels of dehydroepiandrosterone sulfate, testosterone, 17-hydroxyprogesterone (P < 0.001) and androstenedione (P < 0.05) were higher than in the control group. Of the insulin parameters, basal insulinemia, maximum insulin peak, and insulinemia/glycemia index were higher in the patient group (P < 0.001). In patients with marked insulinemia, free testosterone index was more markedly elevated, and gonadotrophin levels were normal. Our data confirm that a characteristic pattern of hyperinsulinemia is associated with PCOS. We found no causal relationship between hyperinsulinemia and androgen levels. A characteristic hormonal pattern was found in patients with marked hyperinsulinemia.Abbreviations BMI body mass index - 17OHP 17-hydroxyprogesterone - DHEAS dehydroepiandrosterone sulfate - FTI free testosterone index - I/G insulin/glucose ratio - OGTT oral glucose tolerance test - PCOS polycystic ovary syndrome - P_max maximun peak of insulin - SHBG sex hormone binding globulin - LH luteinizing hormone - FSH follicle-stimulating hormone