title: Assessment of circulating sex steroid levels in prepubertal and pubertal boys and girls by a novel ultrasensitive gas chromatography-tandem mass spectrometry method.
abstract: BACKGROUND
  Estrogens and androgens play key roles for pubertal onset and sexual maturation. Most currently used immunoassays are not sensitive enough to accurately measure the low circulating levels of sex steroids in children without any signs of puberty. However, this does not exclude that sex steroids have important biological roles in prepubertal children.
  
  
  OBJECTIVE
  To accurately determine levels of sex steroid hormones and their metabolites in serum of healthy children before any physical signs of puberty and to evaluate possible sex differences.
  
  
  METHODS
  Total (unconjugated plus conjugated) serum levels of 17beta-testosterone, 17alpha-testosterone, 5alpha-dihydrotestosterone, 5beta-dihydrotestosterone, androsterone, etiocholanolone, estradiol, and estrone measured by an ultrasensitive method based on gas chromatography-tandem mass spectrometry in samples from 81 healthy schoolchildren (42 boys) without any signs of puberty. For comparison, 48 pubertal children were studied.
  
  
  RESULTS
  17beta-Estradiol levels in prepubertal boys were undetectable or extremely low (median < 3.7 pmol/liter), whereas levels in prepubertal girls were significantly higher (median 9.6 pmol/liter, P < 0.001). Among the older prepubertal children (>8 yr), girls had significantly higher androsterone (4.07 vs. 1.45 nmol/liter, P < 0.05), etiocholanolone (5.45 vs. 1.95 nmol/liter, P < 0.0001), 5alpha-dihydrotestosterone (0.11 vs. <0.10 nmol/liter, P < 0.01), and 17beta-testosterone concentrations (0.69 vs. 0.47 nmol/liter, P < 0.05) compared with similarly aged prepubertal boys.
  
  
  CONCLUSIONS
  Using an accurate and sensitive method, we found significantly higher levels of estrogens as well as androgen metabolites in prepubertal girls compared with age-matched boys. The higher prepubertal sex steroid levels in girls may contribute to their earlier onset of puberty including pubic hair development.
authors.affiliation: Laboratoire d'Etude des Résidus et Contaminants dans les Aliments, Unité Sous Contrat 2013 Institut National de la Recherche Agronomique, Ecole Nationale Vétérinaire de Nantes, F-44307 Nantes, France.
authors.forename: Frédérique
authors.initials: F
authors.lastname: Courant
authors.forename: Lise
authors.initials: L
authors.lastname: Aksglaede
authors.forename: Jean-Philippe
authors.initials: JP
authors.lastname: Antignac
authors.forename: Fabrice
authors.initials: F
authors.lastname: Monteau
authors.forename: Kaspar
authors.initials: K
authors.lastname: Sorensen
authors.forename: Anna-Maria
authors.initials: AM
authors.lastname: Andersson
authors.forename: Niels E
authors.initials: NE
authors.lastname: Skakkebaek
authors.forename: Anders
authors.initials: A
authors.lastname: Juul
authors.forename: Bruno Le
authors.initials: BL
authors.lastname: Bizec
mesh_terms: D000293:Adolescent; D000367:Age Factors; D001774:Blood Chemical Analysis / Q000379:methods / Q000592:standards; D002138:Calibration; D002648:Child; D002849:Chromatography, Gas / Q000379:methods / Q000592:standards; D005260:Female; D012739:Gonadal Steroid Hormones / Q000032:analysis* / Q000097:blood; D006801:Humans; D008297:Male; D011627:Puberty / Q000097:blood* / Q000502:physiology; D015203:Reproducibility of Results; D012737:Sex Factors; D053719:Tandem Mass Spectrometry / Q000379:methods* / Q000592:standards
chemical_list: D012739:Gonadal Steroid Hormones