Tamoxifen inhibits phorbol ester stimulated osteoclastic bone resorption: an effect mediated by calmodulin.

@article{Williams2000TamoxifenIP,
  title={Tamoxifen inhibits phorbol ester stimulated osteoclastic bone resorption: an effect mediated by calmodulin.},
  author={John Michael Williams and Margaret A McKenna and Allyn M Thames and J. M. Mcdonald},
  journal={Biochemistry and cell biology = Biochimie et biologie cellulaire},
  year={2000},
  volume={78 6},
  pages={715-23}
}
Tamoxifen inhibits bone resorption by disrupting calmodulin-dependent processes. Since tamoxifen inhibits protein kinase C in other cells, we compared the effects of tamoxifen and the phorbol ester, phorbol myristate acetate, on osteoclast activity. Phorbol esters stimulate bone resorption and calmodulin levels four-fold (k0.5 = 0.1-0.3 microM). In contrast, tamoxifen inhibited osteoclast activity approximately 60% with an IC50 of 1.5 microM, had no apparent effect on protein kinase C activity… CONTINUE READING