title: Factors associated with fasting plasma ghrelin levels in children and adolescents.
abstract: OBJECTIVE
  To measure plasma ghrelin levels in children and adolescents, analyze the associated factors, and investigate the role of ghrelin in obesity, insulin resistance and reproductive physiology.
  
  
  METHODS
  A total of 283 subjects aged 4.8-15.8 year were enrolled. Fasting blood samples were collected and plasma ghrelin levels were measured by radioimmunoassay. Fasting glucose (FG), fasting insulin (FI), baseline testosterone (T), estradiol (E2), prolactin (PRL), luteinizing hormone (LH), follicle-stimulating hormone (FSH), serum total cholesterol (TC), triglyceride (TG), alanine aminotransferase (ALT) and uric acid (UA) were measured. Body mass index (BMI), insulin resistance by homeostasis model (HOMA-IR) and beta cell function by homeostasis model (HOMA-beta) were calculated.
  
  
  RESULTS
  The median ghrelin level was 290 ng/L (15.0-1325.0 ng/L). Bivariate correlation analysis showed that ghrelin levels were inversely correlated with BMI, ALT, TG, UA, LH, FI and HOMA-IR (all P < 0.05). No other significant correlation was found between ghrelin levels and age, gender, TC, E2, FSH, PRL, FG and HOMA-beta. Stepwise multiple regression analysis showed that only BMI and FI were independent determinants of plasma ghrelin levels in these children and adolescents (P = 0.018 and P = 0.046, respectively), which explained 25.4% of the variance.
  
  
  CONCLUSIONS
  These data suggest that the lower ghrelin levels in obese subjects may be the result of obesity and hyperinsulinemia, which is very common in obese subjects. Moreover, ghrelin may regulate human reproductive physiology indirectly.
authors.affiliation: Department of Endocrinology, the Children's Hospital of Zhejiang University School of Medicine, 57 Zhugan Xiang, Hangzhou 310003, Zhejiang Province, China.
authors.forename: Chao-Chun
authors.initials: CC
authors.lastname: Zou
authors.forename: Li
authors.initials: L
authors.lastname: Liang
authors.forename: Zheng-Yan
authors.initials: ZY
authors.lastname: Zhao
mesh_terms: D000293:Adolescent; D015992:Body Mass Index; D002648:Child; D002675:Child, Preschool; D005215:Fasting; D005260:Female; D054439:Ghrelin / Q000097:blood*; D006801:Humans; D006946:Hyperinsulinism / Q000097:blood* / Q000503:physiopathology; D008297:Male; D009765:Obesity / Q000097:blood* / Q000503:physiopathology; D012098:Reproduction / Q000502:physiology
chemical_list: D054439:Ghrelin