[The endocrine function of the skeleton]

Skeleton has long been recognized as a organ supporting body system and regulating metabolism of calcium and phosphorus. Recent researches found that bone cells, especially osteoblast and osteoclast, synthesize and secrete various bioactive molecules, such as bone morphogenetic proteins, growth factors, adipokines, inflammatory cytokines and cardiovascular bioactive peptides. The active factors produced by bone not only play important roles in the skeleton system per se by paracrine/autocrine pathway but also regulate energy metabolism, inflammatory process, endocrine homeostasis by endocrine pathway.