Clinical Study And Mechanistic Discussions On The Role Of Soluble Leptin Receptor (sOB-R) In Polycystic Ovary Syndrome And Insulin Resistance

OBJECTIVE The aim of this study was to investigate the levels of Soluble Leptin Receptor (sOB-R) in patients with Polycystic ovary syndrome (PCOS) and insulin resistance (IR), the effects of insulin resistance and chronic hyperinsulinemia(HI) on the leptin system, the relationship between HI/IR and PCOS and explore their role in the pathogenesis of PCOS.METHODS 97 patients with PCOS, aged 13～38 (25±5, on average), divided into two groups:hyperinsulinemia group (HI Group, n=60) and non-hyperinsulinemia group (NHI Group, n=37), to investigate the relationship between hyperinsulinemia (HI), insulin resistance (IR) and polycystic ovary syndrome (PCOS). And In order to investigate the levels of Soluble Leptin Receptor (sOB-R) in women with PCOS, from the 97 patients we chose 55 with insulin resistance treated with Metformin for six months. According to body mass index (BMI), they were divided into two subgroups:lean PCOS (BMI＜23 kg/m2, n=34) and overweight or obese PCOS (BMI>25 kg/m2,n=21). Other 31 body mass index (BMI)-matched ovulatory women wee as controls. Both Patients and controls were measured of Age, standing height, weight, waist circumference, hip circumference, Ferriman-Gallwey score(F-G), Rosenfield acne score, body mass index(BMI), luteinizing hormone(LH), follicle stimulating hormone(FSH), prolactin(PRL), testosterone(T), dehydroepiandrosterone (DHEA), androstenedione(A), fasting plasma glucose(FPG), fasting insulin(FINS), oral glucose tolerance test(OGTT), insulin releasing test(IRT), Insulin resistance andβ-cell function were defined by the homeostasis model assessment (HOMA-IR), insulin and sOB-R levels were determined. RESULTS PCOS patients were found to have high indices of androgen levels, hirsutism scores, blood glucose level after OGTT for 30min,60min and 120min and 180 min, FINS, the insulin level after IRT, AUC for glucose and insulin as well as insulin resistance (HOMA-IR). Furthermore, HOMA-IR was positively correlated with waist circumference, hip circumference, BMI, FPG, FIN, GAUC, IAUC and HOMA-IS (every P<0.01). In PCOS pateints sOB-R levels were lawer than controls. No correlation was found between sOB-R and BMI, waist and hip circumference, total testosterone, androstendione, DHEAS, LH or hirsutism scores. However, a significant negative correlation was found between sOB-R and HOMA-IR. After treatment, the sOB-R levels in women with PCOS increased significantly.CONCLUSION HI and IR can promote the development of the obesity in PCOS; they have a close relationship with the disorder of glucose metabolism, which shows a positive significance for its early intervention as well as the prevention of its late complications. Low sOB-R levels in PCOS women as a possible mechanism to compensate for leptin resistance. It is likely that reduction of hyperinsulinemia that is produce by metformin effectively improves the sOB-R levels and improves leptin resistance in PCOS. Decreased sOB-R levels and increased leptin concentrations can be one of the elements of PCOS clinical picture.