Estrogen receptor-alpha and estrogen receptor-beta are present in the human growth plate in childhood and adolescence, in identical distribution.
OBJECTIVE
To localize estrogen receptor-alpha (ER-alpha) and estrogen receptor-beta (ER-beta) within the growth plate and adjacent bony tissue of children in the prepubertal and pubertal age period.


METHODS
Tissue was taken during orthopedic surgery (epiphysiodesis) for correction of congenital or traumatic leg length difference in 2 prepubertal females and 2 adolescent males. Immunohistochemistry was performed on paraffin-embedded or cryostat sections by using commercially available rabbit polyclonal antibodies for ER-alpha and ER-beta.


RESULTS
Both ER-alpha and ER-beta were detected within the growth plate in all sections investigated. Immunostaining was restricted to hypertrophic chondrocytes. In the bony tissue adjacent to the growth plate, osteoblasts stained positive for both ER-alpha and ER-beta, whereas osteocytes and osteoclasts were negative. Staining with ER-alpha was mainly nuclear but some cells also showed cytoplasmic signals, while ER-beta staining was predominantly cytoplasmic, only few nuclei stained positive. There was no difference in the local distribution of both ERs between tissue from prepubertal and pubertal patients.


CONCLUSIONS
Our findings indicate that the hypertrophic chondrocyte is the main target cell for estrogen action within the growth plate. The presence of ER in prepubertal children suggests that estrogens play a role in skeletal maturation under physiological conditions also in this age-group.
Institute of Histology and Embryology, University of Veterinary Medicine, Vienna, Austria.
M
M
Egerbacher
M
M
Helmreich
W
W
Rossmanith
G
G
Haeusler
D000293:Adolescent; D001842:Bone and Bones / Q000378:metabolism; D002675:Child, Preschool; D019902:Chondrocytes / Q000378:metabolism; D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D005260:Female; D006132:Growth Plate / Q000378:metabolism*; D006801:Humans; D007074:Immunoglobulin G; D007150:Immunohistochemistry; D008297:Male; D010006:Osteoblasts / Q000378:metabolism; D011960:Receptors, Estrogen / Q000378:metabolism*; D013234:Stem Cells / Q000378:metabolism; D013977:Tibia / Q000378:metabolism
D047628:Estrogen Receptor alpha; D047629:Estrogen Receptor beta; D007074:Immunoglobulin G; D011960:Receptors, Estrogen