Estrogen and the skeleton

Estrogen is the major hormonal regulator of bone metabolism in women and men. Therefore, there is considerable interest in unraveling the pathways by which estrogen exerts its protective effects on bone. Although the major consequence of the loss of estrogen is an increase in bone resorption, estrogen deficiency is associated with a gap between bone resorption and formation, indicating that estrogen is also important for maintaining bone formation at the cellular level. Direct estrogen effects on osteocytes, osteoclasts, and osteoblasts lead to inhibition of bone remodeling, decreased bone resorption, and maintenance of bone formation, respectively. Estrogen also modulates osteoblast/osteocyte and T-cell regulation of osteoclasts. Unraveling these pleiotropic effects of estrogen may lead to new approaches to prevent and treat osteoporosis. Estrogen is the major hormonal regulator of bone metabolism in women and men. Therefore, there is considerable interest in unraveling the pathways by which estrogen exerts its protective effects on bone. Although the major consequence of the loss of estrogen is an increase in bone resorption, estrogen deficiency is associated with a gap between bone resorption and formation, indicating that estrogen is also important for maintaining bone formation at the cellular level. Direct estrogen effects on osteocytes, osteoclasts, and osteoblasts lead to inhibition of bone remodeling, decreased bone resorption, and maintenance of bone formation, respectively. Estrogen also modulates osteoblast/osteocyte and T-cell regulation of osteoclasts. Unraveling these pleiotropic effects of estrogen may lead to new approaches to prevent and treat osteoporosis. a structural and functional unit in the skeleton that is responsible for bone remodeling. A BMU includes osteoclasts, osteoblasts, and osteocytes within the bone remodeling cavity. the process whereby bone is resorbed and then formed, primarily to help repair microcracks that develop in the skeleton. a structure in bone that consists of the BMU covered by a ‘canopy’ of cells (most probably bone-lining cells). also termed trabecular bone or spongy bone, is one of two types of tissue that forms bones. also termed compact bone, is one of the two types of tissues that forms bones. the inner surface of cortical bone. a cell of mesenchymal origin responsible for forming bone. a cell of hematopoietic origin responsible for resorbing bone. a cell embedded within the bone matrix, derived from the osteoblast that helps to orchestrate bone remodeling. the outer surface of cortical bone.