[Hormones and osteoporosis update. Estrogen and bone remodeling]

Estrogen is quite well known to exert osteoprotective action, and indeed post-menopausal women in estrogen deficiency suffer osteoporotic defects in bone. The molecular basis of such estrogen action had been uncovered, since ER alpha KO mice failed to recapture the osteoporotic phenotype induced by estrogen deficiency in the same mouse strain. Recently, we have selectively disrupted ER alpha gene in mature osteoclasts, and this female mice were found to display a typical osteoporotic bone phenotype. In this review, I briefly overview this aspect.