title: Serum leptin levels correlate with growth hormone secretion and body fat in children.
abstract: The aim of this study was to investigate the relationship among GH secretion, leptin concentrations, and body composition measured with x-ray absorptiometry (DXA) in children. In total, 71 children were investigated, 51 males and 20 females. Their mean chronological age was 10.8 yr (range, 6.2-17.7 ys), and their mean height (SD) was -2.1 (0.63) SD scores. Their mean weight for height SD scores (WH(SDS)) was 0.2 (1.18). Body composition was investigated using DXA. Blood samples were taken for analysis of leptin, insulin-like growth factor I (IGF-I), IGF-binding protein-3, and 24-h GH secretion. A positive correlation was found between leptin and total body fat (r = 0.83; P < 0.0001) and when fat was expressed as a percentage of body weight (r = 0.86; P < 0.0001). There were significant (P < 0.0001) relationships between leptin and WH(SDS) (r = 0.45) and between leptin and body mass index (r = 0.69). A significant gender difference in leptin levels was found, but this disappeared after adjustment for body fat, as measured by DXA. There were significant (P < 0.001) inverse correlations between leptin and the AUCb for GH (r = -0.41), leptin, and GHmax (r = -0.38), where AUCb is the area under the curve above the calculated baseline, and GHmax is the maximum peak during the 24-h GH profile (percent fat and AUCb for GH, r = -0.43; percent fat and GHmax, r = -0.39). In a multiple stepwise forward regression analysis with leptin as the dependent variable, the percent trunk fat accounted for 77.7% of the leptin variation. With AUCb for GH as the dependent variable, the percent trunk fat accounted for 20.3% of the variation. With GHmax as the dependent variable, the percent trunk fat accounted for 18.8% of the variation, IGF-binding protein-3 for another 8.5%, and the percentage of fat from arms and legs for another 4.4%. We demonstrated a strong positive correlation between leptin levels and body fat, a significant negative correlation between leptin levels and GH secretion, and a significant negative correlation between body fat and GH secretion. We have also shown that specific regional fat depots have different relationships with leptin and particular markers of GH secretion.
authors.affiliation: International Pediatric Growth Research Center, Department of Pediatrics, Sahlgrenska University Hospital, Goteborg University, Sweden. hans.fors@mailbox.swipnet.se
authors.forename: H
authors.initials: H
authors.lastname: Fors
authors.forename: H
authors.initials: H
authors.lastname: Matsuoka
authors.forename: I
authors.initials: I
authors.lastname: Bosaeus
authors.forename: S
authors.initials: S
authors.lastname: Rosberg
authors.forename: K A
authors.initials: KA
authors.lastname: Wikland
authors.forename: R
authors.initials: R
authors.lastname: Bjarnason
mesh_terms: D015502:Absorptiometry, Photon; D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000473:pathology; D001823:Body Composition; D001827:Body Height; D002648:Child; D005260:Female; D006130:Growth Disorders / Q000097:blood / Q000378:metabolism / Q000473:pathology; D019382:Human Growth Hormone / Q000378:metabolism*; D006801:Humans; D020738:Leptin / Q000097:blood*; D008297:Male; D015999:Multivariate Analysis; D012016:Reference Values
chemical_list: D020738:Leptin; D019382:Human Growth Hormone