Adipokines level in plasma, hypothalamus, ovaries and adipose tissue of rats with polycystic ovary syndrome

Research question: Do the levels of adipokines (adiponectin, apelin, chemerin and vaspin) in plasma, hypothalamus, ovaries and periovarian adipose tissue differ during polycystic ovarian syndrome (PCOS)? Design: The PCOS was induced in rats by oral administration of non-steroidal aromatase inhibitor letrozole. To determine the plasma levels of adiponectin, apelin, chemerin and vaspin enzyme-linked immunosorbent assays were carried out. To assess the expression (gene and protein) and immunolocalization of these adipokines and their receptors, namely Adipor1 and Adipor2 for adiponectin, Aplnr for apelin, Ccrl2, Cmklr1 and Gpr1 for chemerin and Grp78 for vaspin in the hypothalamus, real-time polymerase chain reaction, and Western blot and immunohistochemistry were used to analyse ovaries and periovarian adipose tissue respectively. Results: In PCOS, the plasma level of adiponectin decreased (P = 0.0003), whereas apelin, chemerin and vaspin increased (P 0.0479). Moreover, PCOS modulates the expression of adipokines and their receptors in the hypothalamus, ovaries and periovarian adipose tissue compared with healthy rats (P 0.487). Conclusions: A strong relationship was found between PCOS and adipokines, which suggests that adipokines may be a biomarker of PCOS.