The Relation of the Sulphur Amino Acids to the Toxicity of Cobalt and Nickel in the Rat

Abstract

The marked inhibition of growth of young rats due to 0.12% of cobaltous sulphate in an 18% casein diet is largely prevented by supplements of methionine, cystine or cysteine, especially the latter. The high mortality due to either the oral or intraperitoneal administration of very toxic levels of either cobalt or nickel is prevented by the simultaneous and separate administration of cysteine. The complex of cobalt and cysteine formed in vitro is relatively non-toxic. Cobalt poisoning may be due to the fixation and loss of sulfhydryl compounds in tissues with resulting interference with oxidative mechanisms.