RESUMEN
Leptin, the product of the ob gene, is a hormone secreted by adipocytes, and results in a decrease in food intake an increase in energy expenditure via hypothalamic interactions. In animal models, obesity can be caused by leptin deficiency or dysfunction of hypothalamic leptin receptor. The aim of this study was to examin the relation between serum leptin levels and body composition. In this study, we measured serum concentration of leptin in 51 normal weight subjects [BMI < 25 kg/m[2]] and 50 obese subjects [BMI >/= 25] by ELISA. BMI was defined as the weight in kilogram divided by the square of height in meters and body composition was determined by bioimpedance analyzer. The mean +/- SE] serum leptin concentrations were 17.5 +/- 0.81 ng per milliliter in obese subjects and 4.9 +/- 0.55 ng per milliliter in the normal weight women [p< 0.0005]. There were a strong positive correlation between serum leptin concentration and body fat mass [r= 0.53] and BMI [r = 0.41] in obese women and lean body mass was inversely related to leptin concentration in normal weight subjects [r = - 0.28]. Significant relation between leptin and WHR neither in obese nor in normal weight group was not observed. We conclude that circulating leptin raised continuously with increasing adiposity and body fat mass is the main predictor of serum leptin concentration