Serum Levels of Angiopoietin-Related Growth Factor (AGF) are Increased in Polycystic Ovary Syndrome

BACKGROUND: Polycystic ovary syndrome (PCOS) is a frequent reproductive and metabolic disorder associated with insulin resistance. Recently, angiopoietins were identified in the systemic circulation and have been designated angiopoietinlike proteins (ANGPTL). More recently, it is shown that angiopoietin-related growth factor (AGF, also called ANGPTL6) directly regulate lipid, glucose, and energy metabolism independent of angiogenic effects in animal studies. The aim of this study was to determine whether there is an association between AGF and PCOS. METHODS: The study included 55 [corrected] patients with PCOS and 30 healthy control women. We analyzed serum levels of AGF and other biochemical and anthropometric markers in all the subjects. RESULTS: This study showed that serum AGF levels were significantly higher in the subjects with PCOS (102.28 ng/mL) than those in the healthy control group (63.08 ng/mL; P < 0.001). Body mass index (24.33 vs 22.11 kg/m; P = 0.017), free testosterone (2.81 vs 2.17 pmol/L; P = 0.009), androstenedione (3.28 vs 2.92 nmol/L; P = 0.033), 17-hydroxyprogesterone (2.72 vs 2.09 ng/mL; P = 0.039), homeostasis model of assessment-insulin resistance (2.65 vs 1.9; P = 0.016), and fasting glucose (107.09 vs 96.18 mmol/L; P = 0.001) were found significantly higher in PCOS group than in control group. But there was no correlation between AGF and these parameters in PCOS group. In addition, no correlation between the AGF and other distinctive features of PCOS was found. CONCLUSIONS: Serum AGF levels were paradoxically increased in patients with PCOS in comparison with data of animal experiments. Further studies are needed to better elucidate the physiologic significance of circulating AGF in human disease.