title: Differential effects of sex hormones on peri- and endocortical bone surfaces in pubertal girls.
abstract: BACKGROUND
  The role of sex steroids in bone growth in pubertal girls is not yet clear. Bone biomarkers are indicators of bone metabolic activity, but their value in predicting bone quality has not been studied in growing girls.
  
  
  OBJECTIVE
  This study examines the association of sex hormones and bone markers with bone geometry and density in pubertal girls.
  
  
  METHODS
  The study was designed as a 2-yr longitudinal study in pubertal girls. Measurements were performed at baseline and at 1- and 2-yr follow-ups.
  
  
  METHODS
  The study was conducted in a university laboratory.
  
  
  METHODS
  A total of 258 10- to 13-yr-old healthy girls at the baseline participated.
  
  
  METHODS
  Peripheral quantitative computed tomography was used to scan the left tibial shaft. Serum 17beta-estradiol (E2), testosterone (T), SHBG, osteocalcin (OC), bone-specific alkaline phosphatase, and tartrate-resistant acid phosphatase isoform 5b were assessed. Data were analyzed using hierarchical linear models with random effect.
  
  
  RESULTS
  E2 was a positive predictor for total bone mineral density (BMD), cortical thickness, and a negative predictor for endocortical circumference but had no predictive value for total bone cross-sectional area or periosteal circumference. T was a positive predictor for total cross-sectional area and periosteal circumference as well as endocortical circumference, and a negative predictor for total BMD. OC was negatively correlated with cortical BMD (R2 = 0.325; P < 0.001).
  
  
  CONCLUSIONS
  In pubertal girls, E2 and T have different influences on bone properties at the long bone shaft. The results suggest that, at the endocortical surface, E2 inhibits bone resorption during rapid growth, and later, after menarche, acts at higher concentrations to promote bone formation. At the periosteal surface, T promotes bone formation, whereas E2 does not affect it. In addition, OC might be used as a predictor of cortical BMD.
authors.affiliation: Department of Health Sciences, University of Jyväskylä, P.O. Box 35 (LL), FIN-40014, Jyväskylä, Finland.
authors.forename: Qingju
authors.initials: Q
authors.lastname: Wang
authors.forename: Markku
authors.initials: M
authors.lastname: Alén
authors.forename: Patrick H F
authors.initials: PH
authors.lastname: Nicholson
authors.forename: Jussi M
authors.initials: JM
authors.lastname: Halleen
authors.forename: Sari L
authors.initials: SL
authors.lastname: Alatalo
authors.forename: Claes
authors.initials: C
authors.lastname: Ohlsson
authors.forename: Harri
authors.initials: H
authors.lastname: Suominen
authors.forename: Sulin
authors.initials: S
authors.lastname: Cheng
mesh_terms: D000135:Acid Phosphatase / Q000097:blood; D000293:Adolescent; D000469:Alkaline Phosphatase / Q000097:blood; D015415:Biomarkers; D015519:Bone Density; D001846:Bone Development / Q000187:drug effects*; D002648:Child; D004958:Estradiol / Q000097:blood; D005260:Female; D012739:Gonadal Steroid Hormones / Q000494:pharmacology*; D006801:Humans; D007527:Isoenzymes / Q000097:blood; D016014:Linear Models; D008572:Menarche / Q000502:physiology; D015675:Osteocalcin / Q000097:blood; D011627:Puberty / Q000502:physiology*; D012738:Sex Hormone-Binding Globulin / Q000378:metabolism; D000071681:Tartrate-Resistant Acid Phosphatase; D013739:Testosterone / Q000097:blood; D013977:Tibia / Q000033:anatomy & histology / Q000254:growth & development
chemical_list: D015415:Biomarkers; D012739:Gonadal Steroid Hormones; D007527:Isoenzymes; D012738:Sex Hormone-Binding Globulin; D015675:Osteocalcin; D013739:Testosterone; D004958:Estradiol; D000469:Alkaline Phosphatase; D000135:Acid Phosphatase; D000071681:Tartrate-Resistant Acid Phosphatase