Retinol-binding protein in nonobese women with polycystic ovary syndrome

Although polycystic ovary syndrome (PCOS) is frequently associated with insulin resistance, cardiovascular disease and various metabolic diseases, the mechanisms linking PCOS to metabolic changes are not fully understood. Retinol-binding protein (RBP) was recently reported as an adipocytokine that may link insulin resistance and lipid metabolism. The aim of this study was to investigate the potential role of RBP in women with PCOS.

Fifty women with PCOS and 40 healthy women, all of whom were age- and weight-matched, were studied. Blood was obtained to determine RBP levels as well as metabolic and hormonal parameters, and the homeostasis model assessment of insulin resistance (HOMA-IR) was calculated for each subject.

The RBP levels were higher (P < 0.01) in women with PCOS after adjusting for age, body mass index (BMI), mean blood pressure, triglyceride (TG), high density lipoprotein (HDL)-cholesterol, low density lipoprotein (LDL)-cholesterol, fasting glucose, fasting insulin, estimated glomerular filtration rate (GFR), LH/FSH, total testosterone and SHBG levels. PCOS status was the strongest predictor of elevated RBP levels. In both the PCOS and control groups, RBP levels were significantly correlated with HOMA-IR (P = 0.03 in the PCOS group; P = 0.01 in controls). In addition, RBP levels were significantly correlated with total cholesterol, LDL-cholesterol and TG levels in PCOS (P < 0.01, P < 0.01 and P = 0.01, respectively).

Higher RBP levels in the PCOS group, when compared to the non-PCOS group, were observed, and this difference may play a role in the pathophysiology found in women with PCOS. Further studies are needed to clarify the role of RBP in these women.