Adiponectin is an adipokine that is decreased in obesity and type 2 diabetes. Women with polycystic ovarian syndrome (PCOS) are obese and are at risk for type 2 diabetes. The objective of the current study was to investigate the relationship of adiponectin to obesity and insulin resistance in women with PCOS and severe insulin resistance.
Thirty women with PCOS and acanthosis nigricans indicating severe insulin resistance were included in the study. Eleven body mass index (BMI)-matched women with normal ovulatory cycles served as controls. Fasting glucose, insulin, and adiponectin levels were measured, and a standard oral glucose tolerance test (OGTT) with insulin levels was performed. To further investigate the role of insulin sensitivity on adiponectin levels, 10 women with PCOS were treated with 4 mg rosiglitazone daily for 6 months and adiponectin levels were measured before and after treatment.
Fasting insulin levels (33.5 +/- 3.8 microU/mL; P <.001) and insulin area under the curve (AUC) during OGTT (536.2 +/- 70.5 microU/mL; P <.01) were higher in women with PCOS, while glucose levels were similar to controls. Adiponectin levels were lower (P <.01) in women with PCOS (5.6 +/- 2.6 microg/mL) compared with controls (8.5 +/- 3.9 microg/mL). There was a significant negative correlation between adiponectin levels and fasting insulin levels (r = -0.40, P = .02), insulin AUC during OGTT (r = -0.47, P = .008), fasting glucose levels (r = -0.45, P = .01), and glucose AUC during OGTT (r = -0.51, P = .003). There was no correlation between BMI and serum adiponectin (r = -0.12, P = .508) in women with PCOS, while there was a negative correlation (r = -0.746, P = .013) in controls. There was a significant (P <.01) increase in adiponectin levels when treated with rosiglitazone, despite unchanged BMI.
These results indicate that in women with PCOS and severe insulin resistance, insulin sensitivity appears to be the major determinant of adiponectin levels rather than adiposity. Low adiponectin levels may predict women with PCOS who are at high risk for developing type 2 diabetes.