Endocrine-metabolic effects of the treatment with pioglitazone in obese patients with polycystic ovary syndrome.

The hyperandrogenism found in polycystic ovary syndrome (PCOS) can be a consequence of hyperinsulinemia as a result of peripheral insulin resistance. Metformin and insulin sensitizers have become a potential therapeutic tool for treating these patients; however, there are few studies with pioglitazone in PCOS. Elevated luteinizing hormone/follicle-stimulating hormone (LH/FSH) ratios and LH hyper-responsivity to stimulation with gonadotropin-releasing hormone (GnRH) are common findings in PCOS. The reason why hyperinsulinemia produces hyperandrogenism and whether insulin action on the pituitary alters gonadotropin liberation remain unknown. In the present study, we evaluated the effect of pioglitazone (30 mg/day for 2 months) on insulin response to an oral glucose tolerance test (OGTT), serum levels of androgens and sex hormone-binding globulin (SHBG), and pituitary gonadotropin response to GnRH stimulation in 15 obese PCOS women. We found a significant decrease in insulin response to the OGTT and also in total and free testosterone levels, an increase in SHBG and a reduction in the LH response to GnRH stimulation after pioglitazone treatment. In conclusion, this short-term treatment with pioglitazone decreased hyperinsulinemia and hyperandrogenemia in obese PCOS patients, and there was a significant reduction in LH response to GnRH stimulation. Further research should be carried out to establish the risks and benefits of pioglitazone, which would assist in the physiopathologic comprehension of PCOS.