LEPTIN IN OBESE CHILDREN

Abstract

Obesity is a desorder of the energy balance. The knowledge of factors that are disregulated in obese humans should be of major importance in the prevention and treatment of obesity. Leptin, cholecistoquinin (CCK) and gastrin releasing peptide (GRP), have been related to the saciety-hunger cycle. The aims of this work were: a) to determine serum leptin, CCK and GRP plasma levels in obese children; and b) to investigate the relation between serum leptin concentration versus body weight, body mass fat, basal serum insulin levels(BSIL), CCK and GRP. Thirty six obese children were studied (18 boys and 18 girls; mean ± SD age was 10,7±3,2 years). The obesity was defined, aproximately, as 120% of ideal body weight. A blood sample was collected from each patient while fasting. Serum leptin and serum insulin were measured by RIA (Linco Research., S.Louis, Mo., and Peninsula Laboratories Inc., Belmont, Ca., respectively). CCK and GRP were also assessed by RIA (Peninsula Laboratories Inc., Belmont, Ca.). Body mass fat (BMF) was determined by impedance measurements (BIA) and anthropomorphic data were calculated from from skin fold (SK) density data. Serum leptin concetrations were 24.51±10 pg/ml (normal 1-7 pg/ml). The CCK levels were 0.54±0.5 pmol/L, and GRP levels were 5.54±1.39 pmol/L (normal 4.20±1.08 and 34.39±3.34 pmol/L, respectively). Serum leptin concentrations correlated well with children weight (r=0.52, p<0.02), Z weight (r=0.53, p<0.02), BMF (r=0.6, p<0.008), SK (r=0.7, p<0.004) and BSIL (r=0.6, p<0.02). We conclude that the simultaneous significant increase of serum leptin concentration and the low CCK an GRP levels found in these obese patients, suggest that the obesity is more likely to be due to central mechanisms regulating food intake than to the presence of defective signaling by adipocites.