Figure 2.

Schematic representation of the influences of estrogen receptor α (ERα) and ERβ on loading-related bone gain in cortical and trabecular bone of male and female mice. Global ERα deletion has been associated with reduced cortical bone gain in female mice but increased cortical bone gain in males following loading.35,36,37 Complete deletion of ERβ increased trabecular bone gain in females and cortical bone gain in both males and females following loading,36 whereas in an earlier study incomplete ERβ deletion impaired cortical bone gain following loading in the ulna of female mice.37 Deletion of either ER does not alter trabecular bone gain following loading in male mice,36 but the effects of double ER deletion or cell type-specific deletions have not been investigated.