The effect of uraemic metabolites on parathyroid extract-induced bone resorption in vitro.

A study is reported of the effects of both pre- and post-dialysis serum and some of the known uraemic metabolites on parathyroid extract-induced bone resorption using an in vitro organ culture system. Serum from uraemic patients prior to haemodialysis was shown to inhibit the action of parathyroid hormone on bone and this inhibitory effect was not present after dialysis. Some of the uraemic metabolites studied and also phosphate exerted an inhibitory effect but the metabolites caused their inhibition at higher concentrations than those which are known to occur in uraemic patients. It is concluded that if uraemic metabolites play a role in vivo then it is probably due to a cumulative phenomenon.