| [ Summary ] |
One function of bone in organisms is to mechanically support the body. Bone tissue is always exposed to mechanical stress, such as gravity and locomotion, and the shape of bone adapts to mechanical loading. Mechanical loading on bones generates extracellular deformation and fluid flow. The mechanical stimuli are translated into mechanical signals, such as mechanical strains and fluid shear stress. Bone-forming cells such as osteocytes and osteoblasts are the mechanosensors. When these cells receive the mechanical stress, they stimulate the production of local regulators for bone metabolism. By the actions of these factors on bone-forming cells and bone-resorbing cells in the bone microenvironment, bone metabohsm is turned over in relation to mechanical stress. Among these regulators, prostaglandins play a central role in the local regulation of bone. In addition, mechanical stress on bones up-regulates the response of bone-forming cells to parathyroid hormone, and thereby parathyroid hormone and prostaglandins synergistically stimulate local bone metabolism. |