Chemical modifications of metallothionein, II. Metabolic fate of cadmium bound to metallothionein polymers.

The factors which determine the deposition of cadmium (Cd) were investigated. While intravenously administered Cd2+ salts result in Cd2+ binding loosely to plasma proteins, and subsequently being deposited in the liver, Cd complexed with metallothionein remains tightly bound during glomerular filtration, and most of the dose of Cd is deposited in the kidney. 2 Different chemically crosslinked polymers of MT have been prepared. Cadmium bound to these polymers remains in circulation longer than any other known form of the metal, and the reticuloendothelial system plays a part in its clearance. Using these species, mechanisms of distribution and metabolism of Cd-protein complexes are discussed.