Heterogenous origins of hyperandrogenism in the polycystic ovary syndrome in relation to body mass index and insulin resistance

Background: Insulin resistance and obesity are not universal features of polycystic ovary syndrome (PCOS). We planned to assess the differences between patients with nonobese/insulin-sensitive phenotype vs. obese/insulin-resistant phenotype in terms of the potential mechanisms underlying their hyperandrogenism. Materials and methods: A total of 52 women satisfying Androgen Excess Society (AES) criteria were included. Hormonal and metabolic profile including prolactin, dehydroepiandrosterone sulfate (DHEAS), free testosterone, sex hormone binding globulin (SHBG), fasting plasma glucose and insulin were measured in follicular phase. Results: DHEAS was found to be higher in the nonobese patients as compared to the obese (p = 0.01). There was also a strong trend for a higher DHEAS among patients with lower insulin resistance by homeostatic model assessment (HOMA-IR<2.3) (p = .06).While the total testosterone (p = .044) and SHBG (p = .007) were found to be lower in the more insulin-resistant group (HOMA-IR >= 2.3), the free testosterone levels were similar. However, the percentage of free testosterone was higher in the more insulin-resistant group (p = .005). Conclusions: The hyperandrogenic state in PCOS appears to have heterogenous origins. Nonobese patients with PCOS have adrenal hyperandrogenism as the underlying mechanism while their obese/insulin-resistant counterparts have low SHBG and hence an increased fraction of free testosterone.