Properties of Mercury and Selenium in a High-molecular Weight Substance in Rabbit Tissues Formed by Simultaneous Administration

The properties of mercury and selenium existing in high-molecular weight substance(s) (HMWS) obtained from plasma, stroma-free hemolysate, soluble and insoluble fractions of the liver of rabbits dosed with mercuric chloride and selenite were studied. Analytical procedures--gel filtration, ion exchange chromatography, and sucrose density gradient ultracentrifugation--showed that equimolar amounts of mercury and selenium were present in HMWS in the blood and the liver. Dialysis against mercaptoethanol suggested that selenium and mercury were tightly bound to HMWS in the liver soluble fraction. The formation of the HMWS may contribute to reducing the toxicity of both mercury and selenium. Since mercury and selenium in HMWS in the blood and the liver were present in smaller fragments after trypsin digestion, these HMWS appeared to be protein associated with mercury and selenium. However, after exhaustive digestion with Pronase, mercury and selenium in HMWS were rendered insoluble. The above process appears to take in the body of rabbits after simultaneous administration of mercury and selenium, because the livers excised from these rabbits were found to contain iso-molar and sodium dodecyl sulfate-insoluble selenium and mercury which increased in amount with time.