Demonstration of estrogen receptor-beta immunoreactivity in human growth plate cartilage

Estrogens affect longitudinal bone growth through their action on endochond ral bone formation. Two estrogen receptors are known, the classical estroge n receptor-alpha (ER-alpha), newly demonstrated in human growth plate carti lage, and a recently cloned estrogen receptor-beta (ER-beta). The present s tudy aimed to localize a possible expression of ER-beta protein in human gr owth plates. Tissue samples were obtained from tibial and femoral growth pl ates in four female pubertal patients undergoing epiphyseal surgery. Immuno histochemistry, using two different ER-beta-specific antibodies, demonstrat ed positive staining ER-beta in hypertrophic epiphyseal chondrocytes from a ll patients. No staining was noted in resting or proliferative chondrocytes . These data suggest that in addition to ER-alpha, human epiphyseal chondro cytes also express ER-beta. The physiological role of ER-beta in the regula tion of longitudinal bone growth in humans remains to be elucidated.