Extracellular calcium increases free cytoplasmic calcium and DNA synthesis in human osteoblasts.

Abstract

A high concentration of extracellular calcium (8 mM) induced an increase in free cytoplasmic calcium, a lower cyclic AMP level and increased DNA synthesis in primary cultures of human osteoblast-like cells. Inhibition of protein kinase C with bisindolylmaleimide I inhibited the stimulatory effect of extracellular calcium on DNA synthesis in human osteoblast-like cells, whereas inhibition of protein kinase A with Rp-cAMPs had no effect on DNA synthesis. This indicates that protein kinase C, possibly via increased free cytoplasmic calcium, mediates the effect of extracellular calcium on DNA synthesis in osteoblast-like cells rather than a relative decrease in cyclic AMP and protein kinase A activity. Furthermore, a low concentration (0.5 mM) of extracellular calcium decreased DNA synthesis. In conclusion, these data suggest that a high extracellular calcium level may be a coupling factor that recruits osteoblasts in the bone remodeling process, and that a low level of extracellular calcium may also regulate osteoblast function.

Cite this paper

@article{Tsai2004ExtracellularCI, title={Extracellular calcium increases free cytoplasmic calcium and DNA synthesis in human osteoblasts.}, author={Jon A. Tsai and Elisabet Bucht and O. Torring and H. Kindmark}, journal={Hormone and metabolic research = Hormon- und Stoffwechselforschung = Hormones et metabolisme}, year={2004}, volume={36 1}, pages={22-6} }