[Homeostasis and Disorder of Musculoskeletal System.Humoral factors produced by osteocytes as druggable targets for skeletal diseases.]

Osteocytes have several functions such as sensing mechanical load to bone and regulating osteoclastic bone resorption. In addition, osteocytes secrete several humoral factors that affect bone and other organs. FGF23 produced by osteocytes works as a hormone that reduces serum phosphate level. Sclerostin suppresses bone formation by inhibiting Wnt signals. Drugs that inhibit the activities of these factors are now under investigation as new therapeutic measures.