Differences in distribution and excretion of selenium and cadmium or mercury after their simultaneous administration subcutaneously in equimolar doses.

Forty-eight hours after the simultaneous administration of either 1.8 mumoles Se (as Na2SeO3) to 200 g male rats with equivalent doses of Cd (as CdCl2) or 0.5 mumoles Se with equivalent doses of Hg (as HgCl2) the retention of selenium at the subcutaneous injection site was affected only when it was given in a single injection with the heavy metal. The retention of cadmium was increased only if selenium was injected separately and the retention of mercury was increased both in single and separate injections. When there was an increase in retention at the site of injection, this made up less than 8% of the dose for selenium and mercury and 3% for cadmium and thus could not explain either changes in distribution or the reported protective effects by one metal against the other. The shift in the distributionpattern of one metal caused by the other metal was similar, and independent of whether they were injected in single or separate injections. However the shift in the distribution of interacting metals showed some differences indicating that interaction could not be mediated through the formation of a stable complex between selenium on the one hand and mercury or cadmium on the other.