The effect of trithiomolybdate and some selenium compounds upon 109Cd labeled rat metallothionein in vitro: the possibilities for cadmium chelation therapy.

The main binding protein for 109Cd was metallothionein after in vitro incubation of various tissue cytosol preparations obtained from rats supplemented with zinc. The exception was heart cytosol where the label was associated with higher molecular weight proteins. The metallothionein-bound 109Cd was sensitive to trithiomolybdate and moved too higher molecular weight proteins, presumably because of the creation of new stronger ligands by the association of thiomolybdate with these proteins. The 109Cd binding was affected by selenate, selenite, and selenide while molybdate, sulphate, and thiosulphate were ineffective. It is proposed that thiomolybdates should be investigated for use in the therapy of in vivo cadmium toxicity because they can remove the accumulated metal from metallothionein.