Effects of chelating agents on biliary and urinary excretion and tissue distribution of cadmium in rats

Sodium N-benzyl-D-glucamine dithiocarbamate (NBG-DTC), which was newly synthesized, sodium N-methyl-D-glucamine dithiocarbamate (NMG-DTC), and 2,3-dimercapto-1-propanol (BAL) were evaluated for their efficacy in mobilization of cadmium from the body using rats which had received cadmium, 30 min and 24 h earlier. At both 30 min and 24 h after treatment with cadmium, these chelating agents significantly enhanced the biliary excretion of cadmium, but did not influence the urinary excretion of the metal. Such an enhancement effect of NBG-DTC on the biliary excretion of cadmium was much larger than that of NMG-DTC or BAL. These chelating agents were effective in mobilizing cadmium from the liver at 30 min after pretreatment with cadmium. NBG-DTC showed the largest effectiveness on the depression of cadmium content in the liver. However, the contents of cadmium in the liver and kidney of rats given cadmium, 24 h earlier, did not significantly change at 3 h after treatment with the chelating agents. These results show that the injection of NBG-DTC at both 30 min and 24 h after treatment with cadmium can much more effectively mobilize cadmium from the body mainly through the bile without redistribution of cadmium to tissues than injection of NMG-DTC and BAL.