Ghrelin is an Osteoblast Mitogen and Increases Osteoclastic Bone Resorption In Vitro
Ghrelin increases bone resorption by mature rat osteoclasts. Osteoclasts were incubated on bovine bone slices for 24 hours, and the number of TRAP-positive multinucleated cells on each bone slice was counted. Cells were then removed, the bone slices were stained with toluidine blue, and the number of excavated pits was determined by reflected light microscopy. The results are expressed as the ratio of the number of pits to the number of osteoclasts on a bone slice, with 6–12 bone slices in each group. MNC: multinucleated cells. sCT: salmon calcitonin (positive control). Data are mean ± SEM; *indicates compared to untreated control.