Retinol-binding protein 4, leptin, and insulin resistance in idiopathic hirsutism and hirsute women with polycystic ovary syndrome

Background Idiopathic hirsutism (IH) and polycystic ovary syndrome (PCOS) are the most common causes of hirsutism. Many studies have examined the relationship between retinolbinding protein 4 (RBP4), leptin, and insulin resistance (IR) in patients with PCOS and the association of IR and leptin with IH. To our knowledge, there are no published data on the role of RBP4 in IH. Objective To evaluate the possible role of RBP4, leptin, and IR in IH compared with PCOS and healthy controls. Patients and methods The study included 14 patients with IH (group I) and 11 hirsute patients with PCOS (group II), and 13 healthy women serving as a control group. Serum RBP4 and leptin were measured by enzyme-linked immunosorbent assay. IR was determined using homeostasis model assessment-insulin resistance (HOMA-IR). Hormonal assessment was carried out for all patients. ResultsThe RBP4 level was significantly higher in each patient of group I and group II compared with the controls (Po0.001 for each). No significant difference was detected in HOMA-IR between group I (IH) and the control group, whereas group II (PCOS) had significantly more HOMA-IR than the control group (Po0.001). Leptin levels in groups I and II did not show a significant difference compared with the control group. There was no significant difference in these three parameters between groups I and II. The RBP4 levels of group II (PCOS) were correlated positively with both age and BMI. Leptin levels were correlated negatively with testosterone in group I (IH) and with BMI in group II (PCOS). Conclusion RBP4 may be involved in the pathogenesis of IH as PCOS. Patients with IH, similar to PCOS, may need to be strict in decreasing their body weight.