Adipokines, insulin-like growth factor binding protein-3 levels, and insulin sensitivity in women with polycystic ovary syndrome

Background/Aims: Many women with polycystic ovary syndrome (PCOS) exhibit insulin resistance. Adipose tissue plays an important role in insulin resistance, and adipokines including tumor necrosis factor (TNF)-α and adiponectin are altered in PCOS. Insulin-like growth factor binding protein-3 (IGFBP-3), alone or in conjunction with other adipokines, is also associated with insulin resistance. We evaluated the effects of TNF-α, adiponectin, and IGFBP-3 on insulin sensitivity and the relationships among these proteins in women with PCOS. Methods: We recruited 40 women with PCOS and 40 age- and body mass index (BMI)-matched regular cycling women (controls). The women were divided into obese (BMI ≥ 25 kg/m²) and nonobese (BMI < 25 kg/m²) groups. Anthropometric measurements were performed, and serum levels of TNF-α, adiponectin, and IGFBP-3 were determined. Insulin sensitivity was estimated using the metabolic clearance rate (MCR) of glucose calculated from the oral glucose tolerance test. Results: Serum levels of TNF-α and IGFBP-3 did not differ between the PCOS and control groups, but adiponectin levels in the PCOS group were lower than those in control women in the nonobese group (p < 0.05). TNF-α, adiponectin, and IGFBP-3 levels were not correlated with each other in women with PCOS, but a significant positive correlation was observed between adiponectin levels and MCR (p < 0.05). Multiple regression analysis revealed that adiponectin levels were significantly associated with insulin sensitivity (p < 0.05) in women with PCOS. Conclusions: IGFBP-3 and TNF-α levels were not associated with insulin sensitivity, but adiponectin levels were related to insulin sensitivity in women with PCOS.