[Role of estrogen signaling in male bone]

Although estrogen and its receptors (ERalpha and ERbeta) are requisite in male for functions such as reproductive tract, sexual behavior, maintenance of the skeleton, yet essential in female for normal functions. Genetically modified mouse models, and mutation research in human provide new insights for the roles of estrogen signaling in skeletal effects in both genders. Both of genders have androgen and estrogen, and also its receptors. In general, loss of sex steroid causes bone loss, on the other hand, addition of sex steroid maintain bone mass in both of sex. It seems that the differences are its quantity, balance, and expression patterns. The estrogen action regulates the transcription of estrogen responsive genes mediated by distinct estrogen receptors (ERalpha and ERbeta). So far, the mechanism of specific estrogen action is still not clear in bone remodeling in vivo . Here we discuss the role of estrogen signaling in male bone and its current topics of estrogen signaling.