Differential effects of sex hormones on peri- and endocortical bone surfaces in pubertal girls.
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.
Wang
Qingju
Q
Department of Health Sciences, University of Jyväskylä, P.O. Box 35 (LL), FIN-40014, Jyväskylä, Finland.
Alén
Markku
M
Nicholson
Patrick H F
PH
Halleen
Jussi M
JM
Alatalo
Sari L
SL
Ohlsson
Claes
C
Suominen
Harri
H
Cheng
Sulin
S
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
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