Effect on Insulin-Stimulated Release of D-Chiro-Inositol-Containing Inositolphosphoglycan Mediator during Weight Loss in Obese Women with and without Polycystic Ovary Syndrome

Background. A deficiency of D-chiro-inositol-inositolphosphoglycan mediator (DCI-IPG) may contribute to insulin resistance in polycystic ovary syndrome (PCOS). Whether the relationship between impaired DCI-IPG release and insulin resistance is specific to PCOS rather than obesity is unknown. We assessed insulin-released DCI-IPG and its relationship to insulin sensitivity at baseline and after weight loss in obese women with and without PCOS. Methods. Obese PCOS (n = 16) and normal (n = 15) women underwent 8 weeks of a hypocaloric diet. The Matsuda index, area under the curve DCI-IPG (AUC(DCI-IPG)), AUC(insulin), and AUC(DCI-IPG)/AUC(insulin) were measured during a 2 hr OGTT at baseline and 8 weeks. Results. PCOS women had lower AUC(DCI-IPG)/AUC(insulin) at baseline and a significant relationship between AUC(DCI-IPG)/AUC(insulin) and Matsuda index (p = 0.0003), which was not present in controls. Weight loss was similar between PCOS (−4.08 kg) and normal women (−4.29 kg, p = 0.6281). Weight loss in PCOS women did not change the relationship between AUC(DCI-IPG)/AUC(insulin) and Matsuda index (p = 0.0100), and this relationship remained absent in control women. Conclusion. The association between AUC(DCI-IPG)/AUC(insulin) and insulin sensitivity was only found in PCOS but not in normal women, and this relationship was unaffected by weight loss. DCI and its messenger may contribute to insulin resistance in PCOS independent of obesity.