The relationship between lipocalin-2 and free testosterone levels in polycystic ovary syndrome

Lipocalin-2 is an adipokine that is mainly produced from adipocytes and macrophages. Data related to PCOS and other obesity-associated disorders have shown divergent results. Here, we studied lipocalin-2 concentrations in women with PCOS and in healthy women, and investigated the potential contributors underlying lipocalin association with PCOS.

Forty-four women with PCOS and 47 age- and BMI-matched healthy women were enrolled. Fasting serum glucose, insulin, homeostasis model assessment of insulin resistance (HOMA-IR), high-sensitivity C-reactive protein (hs-CRP), and free testosterone levels were measured. The body fat percentage was measured by bioelectrical impedance.

Lipocalin-2 concentrations were significantly higher in the PCOS group than in the control group (55.74 ± 17.54 ng/mL vs. 36.46 ± 19.62 ng/mL, p = 0.011). There was a correlation between lipocalin-2 levels and free testosterone. In a multiple regression model, the body fat percentage, HOMA-IR, and hs-CRP were not associated with lipocalin-2. However, only free testosterone was associated with lipocalin-2. A "lipocalin-2 = 11.214 + (1.943 × free-testosterone)" equation was obtained.

Serum lipocalin-2 levels were higher in women with PCOS, and only free testosterone was associated with lipocalin-2. Lipocalin-2 levels and their influencing factors have discrepant results in both PCOS and other obesity- or insulin resistance-related metabolic disorders. Thus, the potential role of lipocalin-2 in PCOS should be clarified. (Endokrynol Pol 2017; 68 (1): 7-12).