title: Pubertal growth and serum testosterone and estradiol levels in boys.
abstract: OBJECTIVE
  To study serum testosterone and estradiol in healthy boys in relation to growth during puberty up to peak height velocity (PHV).
  
  
  METHODS
  Growth velocity was analyzed through testosterone (n = 41) and 17β-estradiol (n = 37) 24-hour profiles in a dose-response model. Participants were 26 healthy boys admitted for short or tall stature or participating as healthy volunteers at the Queen Silvia Children's Hospital. Other inclusion criteria included the following: gestational age 37-42 weeks, birth weight and length >-2 standard deviation score (SDS) and prepubertal height and weight within ± 3 SDS. Testosterone was measured using a modified radioimmunoassay (RIA) with a detection limit of 0.03 nmol/l. Estradiol was determined using an ultrasensitive extraction RIA with a detection limit 4 pmol/l. A sixth-grade polynomial was fitted to each child's growth data, giving growth velocity and age at PHV.
  
  
  RESULTS
  Growth velocity increased by 50% from prepubertal growth to PHV at a morning testosterone level of 3.1 nmol/l (95% confidence interval 2.4-4.2), EC50. The corresponding EC50 of 17β-estradiol was 6.5 pmol/l (3.2-13). Boys approaching PHV (<4% remaining) had morning testosterone levels >10 nmol/l and 17β-estradiol >9 pmol/l.
  
  
  CONCLUSIONS
  Observed early puberty/initial mid puberty morning testosterone levels of 2.4-4.2 nmol/l are associated with a 50% increase in growth velocity from prepubertal growth to PHV in healthy boys.
authors.affiliation: Göteborg Pediatric Growth Research Center, Institute of Clinical Sciences, The Sahlgrenska Academy at the University of Gothenburg, Gothenburg, Sweden.
authors.forename: Anna-Karin
authors.initials: AK
authors.lastname: Albin
authors.forename: Ensio
authors.initials: E
authors.lastname: Norjavaara
mesh_terms: D000293:Adolescent; D001827:Body Height; D002648:Child; D004958:Estradiol / Q000097:blood*; D006128:Growth / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D008297:Male; D011627:Puberty / Q000502:physiology*; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone; D004958:Estradiol