Relationships between free leptin and insulin resistance in women with polycystic ovary syndrome

Background: Leptin is an adipokine that circulates in a free form and bound to a soluble leptin receptor. Patients with polycystic ovary syndrome have increased insulin resistance and high incidence of obesity.
Objective: This study was carried out to evaluate levels of leptin and free leptin in women with polycystic ovarian syndrome (PCOS) and note any relationships with insulin resistance and adiposity.
Materials and Methods: We assessed the correlation of metabolic parameters with the levels of free leptin and it’s bound form in 27 PCOS women (aged 26±5.6 years) and 27 healthy women with normal menstrual cycle as controls (aged 25 ±4 years).Total leptin and insulin levels were measured using ELISA. Free leptin form was purified by Gel filtration chromatography and their collected fractions were measured by a sensitive ELISA-Kit. Insulin resistance was calculated by homeostasis model assessment (HOMA).
Results: In PCOS patients and control group a correlation between leptin and body mass index (BMI) was found. A significant difference was found between leptin and free leptin levels in PCOS subjects and controls (p<0.05). Significant correlations were found between free and total leptin with insulin resistant in PCOS subjects (r=0.78 p=0.00, r=0.84 p=0.003) and control groups respectively (r=0.86 p=0.00, r=0.69 p=0.00).
Conclusion: Total and free leptin forms are correlated significantly with BMI in patients with PCOS and in controls. Total and free leptin forms showed significant correlations with insulin resistance but no significant difference was seen in the two groups investigated.