Osteocytes use estrogen receptor alpha to respond to strain but their ERalpha content is regulated by estrogen.

Unlabelled: The role of mechanical strain and estrogen status in regulating ERalpha levels in bone cells was studied in female rats. OVX is associated with decreased ERalpha protein expression/osteocyte, whereas habitual strain and artificial loading has only a small but positive effect, except on the ulna's medial surface, where artificial loading stimulates reversal of resorption to formation.

Introduction: Osteoporosis is the most widespread failure of bones' ability to match their architectural strength to their habitual load bearing.

Osteoblast-like cells from estrogen receptor alpha knockout mice have deficient responses to mechanical strain.

Introduction: In vivo, bones' osteogenic response to mechanical loading involves proliferation of surface osteoblasts. This response is replicated in vitro and involves ERK-mediated activation of the estrogen receptor (ER) alpha and upregulation of estrogen response element activity. This proliferative response can be blocked by selective estrogen receptor modulators and increased by transfection of additional ERalpha.