Effects of Pioglitazone on Insulin and Glucose Metabolism in Women With Polycystic Ovary Syndrome (PCOS)

Our hypothesis is that hyperinsulinemia increases the renal clearance of D-chiro-inositol (DCI) in women with polycystic ovary syndrome (PCOS) and that this leads to a reduction in circulating insulin-stimulated D-chiro-inositol-containing inositol phosphoglycan (DCI-IPG) release. To assess the effects of a chronic reduction in circulating insulin on DCI metabolism, we propose to reduce circulating insulin in obese women with PCOS by improving insulin sensitivity with the drug pioglitazone. Pioglitazone is a thiazolidinedione that improves peripheral insulin sensitivity, presumably by activation of the peroxisome proliferator-activated receptor gamma (PPARγ) receptor. Administration of pioglitazone to women with PCOS has been shown to improve insulin sensitivity, reduce insulin secretion, and decrease both fasting and post-prandial serum insulin concentrations.