Abstract
In vitro bone culture technique was developed by the modification of the Goldhaber's method. Using this method, pyrophosphate was found to inhibit PTH induced bone resorption as judged by the release of previously incorporated Ca45 into the medium and by the histological findings. Furthermore, addition of pyrophosphate markedly enhanced the thyrocalcitonin inhibition of bone resorption in this system. These findings, together with the previous findings that pyrophosphate enhances the hypocalcemic response to TC in vivo, strongly suggest the favorable effect of the combined use of pyrophosphate and TC in the bone diseases characterized by excessive bone resorption.