Serum leptin level in obese women with polycystic ovary syndrome, and its relation to insulin resistance

ObjectiveTo compare serum leptin levels in obese women with polycystic ovary syndrome (PCOS) and normal ovulatory obese subjects in Saudi Arabia, and to evaluate the interrelationship between leptin concentration, sex hormones, and insulin resistance.MethodsThe present study was conducted on 40 women with PCOS (34.30 ± 2.08 years, body mass index (BMI) 34.84 ± 4.77 kg/m2, mean ± SD) and 16 obese women as control group (28.10 ± 4.61 years, BMI 33.59 ± 1.23 kg/m2). Diagnostic criteria for PCOS based on the presence of two out of three traits including oligo –and/or anovulation, clinical and/or biochemical signs of hyperandrogenism and the presence of polycystic ovaries on ultrasound scan. Concentrations of testosterone, progesterone, prolactin, gonadotrophins, glucose, insulin, and leptin were measured in the baseline fasting blood sample. Serum leptin concentrations were measured by enzyme linked immunosorbant assay.ResultsSerum leptin levels in PCOS patients were significantly higher than that in the control group (P=0.005) independently of BMI, and were significantly different between insulin resistant and non-insulin resistant obese PCOS (P=0.044), In PCOS patients there was a positive correlation between leptin and BMI (P=0.049), and there was no correlation between leptin and other hormonal indices in PCOS patients.ConclusionsThe study revealed that the body mass index and insulin resistance are the two main factors governing serum leptin levels.