Osteoclast has specific receptor for:
Hormones Bone cells on which their receptors are present
Calcitonin →Osteoclasts →Directly inhibit its function (i.e. Resorption)
Parathyroid →Osteoblasts → Activate its function
Vitamin D →Osteoblasts → Activate its function
I. Bone resorption is the normal destruction of bone by osteoclasts, which are indirectly stimulated by PTH.
II. Stimulation is indirect since osteoclasts do not have a receptor for PTH; rather, PTH binds to osteoblasts, the cells responsible for creating bone.
III. Binding stimulates osteoblasts to increase their expression of RANKL, which can bind to osteoclast precursors containing RANK, a receptor for RANKL. The binding of RANKL to RANK stimulates these precursors to fuse, forming new osteoclasts which ultimately enhances the resorption of bone.
IV. The calcitonin receptor, found primarily on osteoclasts, is a G protein-coupled receptor, which is coupled by Gs to adenylyl cyclase and thereby to the generation of cAMP in target cells.