title: Serum leptin in children with obesity: relationship to gender and development.
abstract: BACKGROUND
  The identification of the ob gene and its adipocyte-specific protein leptin has provided the first physiologic links to the regulatory system controlling body weight. In adults, elevations of serum leptin concentrations were closely correlated with the percentage of body fat. This study investigated whether leptin concentrations were elevated in obese children and the relationship between leptin concentrations and gender, pubertal stage, and race.
  
  
  METHODS
  Seventy-seven children (44 girls and 33 boys), mean age, 11.3 years, with a body mass indices (BMIs) greater than 95% for age, race, and gender (mean BMI, 34.4) constituted the obese group. Thirty children (20 girls and 10 boys), mean age, 13.3 years, with BMIs less than 85% for age, race, and sex formed the control group. Radioimmunoassay for serum leptin was performed on a blood sample collected from each child after an overnight fast.
  
  
  RESULTS
  The mean serum concentration of leptin in the obese group was 38.6 (SD, 21) ng/mL compared with 7.8 (SD, 6.5) ng/mL in the control group. Serum leptin concentrations were highly correlated with BMI (r = .88). Analysis of covariance revealed a main effect for Tanner stage and gender.
  
  
  CONCLUSIONS
  As in adults, obese children have high concentrations of serum leptin, which were highly correlated with arm fat and BMI. Increased adipose tissue in children is associated directly with serum leptin concentration. Leptin concentrations were found to vary with Tanner stage independent of adiposity. Compared with boys, girls had increased leptin concentrations independent of adiposity. It was hypothesized that children manifest a relative "leptin resistance" to support increased growth and development of reproductive capacity.
authors.affiliation: Department of Pediatrics, Alfred I duPont Institute, Wilmington, DE 19899, USA.
authors.forename: S G
authors.initials: SG
authors.lastname: Hassink
authors.forename: D V
authors.initials: DV
authors.lastname: Sheslow
authors.forename: E
authors.initials: E
authors.lastname: de Lancey
authors.forename: I
authors.initials: I
authors.lastname: Opentanova
authors.forename: R V
authors.initials: RV
authors.lastname: Considine
authors.forename: J F
authors.initials: JF
authors.lastname: Caro
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000293:Adolescent; D015992:Body Mass Index; D016022:Case-Control Studies; D002648:Child; D002657:Child Development; D005260:Female; D006128:Growth; D006801:Humans; D020738:Leptin; D008297:Male; D009765:Obesity / Q000097:blood* / Q000208:ethnology / Q000235:genetics; D011506:Proteins / Q000032:analysis* / Q000235:genetics; D044469:Racial Groups; D012737:Sex Factors
chemical_list: D020738:Leptin; D011506:Proteins