Effect of extracellular calcium concentrations on osteoclast differentiation in vitro

We have been researching with the purpose of understanding the hard organiz ation mineralization-suppression mechanism under a low calcium environment. So far, we have discerned clearly that the femur of an incubated newborn r at under a low calcium environment will develop bone formation dyscrasia su ch as hypertrophy of the caput. In this experiment, MC3T3-E1 (El) cells, wh ich are osteoblast-like cells, and mouse bone marrow were incubated in a co culture system under a low calcium environment and manifestation of osteobl ast cells and their ability to resorb were examined. The results suggested that as the calcium concentration in the medium decreased manifestation of osteoclast cells increased, and as the degree of mineralization of El cells advanced, the number of manifestation of osteoblast cells decreased. We, t herefore, report that there is a possibility that extracellular calcium con centrations involve the process of differentiation of bone marrow cells int o osteoblast cells. (C) 1999 Academic Press.