title: Age-dependent elevations in plasma kisspeptin are observed in boys and girls when compared with adults.
abstract: BACKGROUND
  Kisspeptin is a hypothalamic neuropeptide playing a physiological role in human reproduction. Genetic over-activation of kisspeptin causes precocious puberty in children. Concentrations of circulating kisspeptin are low in adults. The concentrations of plasma kisspeptin in boys and girls have not been studied previously.
  
  
  METHODS
  Blood was obtained from 51 children and 63 adults. Plasma samples were analysed using radioimmunoassay. Children were aged 2-18 years, and attending hospital for a medically requested blood test unrelated to reproductive development. Data on pubertal status were not collected due to ethical reasons.
  
  
  RESULTS
  Mean plasma kisspeptin was significantly higher in children when compared with adults (mean plasma kisspeptin in pmol/L: 12.3 ± 0.9, adults; 40.9 ± 3.3, children, P < 0.001 vs. adults). Overall mean concentrations of plasma kisspeptin were not significantly different between sexes (mean plasma kisspeptin in pmol/L: 39.5 ± 3.2, boys; 44.3 ± 6.3, girls, P = 0.48). In both sexes, concentrations of plasma kisspeptin increased with age to peak concentrations between 9 and 12 years of age, before decreasing beyond 12 years of age to adulthood. Plasma kisspeptin concentrations were highly significantly elevated in both girls and boys aged 9-12 when compared with adults (mean plasma kisspeptin in pmol/L: 59.5 ± 18.3, girls, P < 0.01 vs. adult women; 43.8 ± 6.2, boys, P < 0.001 vs. adult men).
  
  
  CONCLUSIONS
  We report that circulating kisspeptin is elevated in both boys and girls when compared with adults. Furthermore both boys and girls may have distinct, age-dependent concentrations of circulating kisspeptin. Further studies may determine if plasma kisspeptin could be used as a clinically useful biochemical marker of reproductive development in children.
authors.affiliation: Department of Investigative Medicine, Imperial College London, Hammersmith Hospital, London, UK.
authors.forename: Channa N
authors.initials: CN
authors.lastname: Jayasena
authors.forename: Gurjinder M K
authors.initials: GM
authors.lastname: Nijher
authors.forename: Shakunthala
authors.initials: S
authors.lastname: Narayanaswamy
authors.forename: Akila
authors.initials: A
authors.lastname: De Silva
authors.forename: Ali
authors.initials: A
authors.lastname: Abbara
authors.forename: Mohammad A
authors.initials: MA
authors.lastname: Ghatei
authors.forename: Stephen R
authors.initials: SR
authors.lastname: Bloom
authors.forename: Nicola
authors.initials: N
authors.lastname: Bridges
authors.forename: Waljit S
authors.initials: WS
authors.lastname: Dhillo
mesh_terms: D000293:Adolescent; D000328:Adult; D000367:Age Factors; D015415:Biomarkers / Q000097:blood*; D002648:Child; D002675:Child, Preschool; D005260:Female; D006801:Humans; D059648:Kisspeptins / Q000097:blood*; D008297:Male; D011629:Puberty, Precocious / Q000097:blood*; D011863:Radioimmunoassay; D012098:Reproduction / Q000502:physiology*
chemical_list: D015415:Biomarkers; D059648:Kisspeptins
keywords: KISS1; Kisspeptin; children; puberty