Fate and comparative toxicity of metallothioneins with differing Cd/Zn ratios in rat kidney

Metallothioneins with differing Cd/Zn ratios were prepared in vitro from rat liver zinc-thionein by replacing zinc with cadmium and were injected intraperitoneally to female rats. The distribution of cadmium, zinc, and copper in the kidney supernatant fraction was determined using a Sephadex G-75 column. The distribution pattern of cadmium and zinc changed dramatically within 24 hr after the injection. The changes were explained by the degradation and re-synthesis of metallothionein in the kidneys. The necrotic changes of renal tubular lining cells were correlated to the amount of cadmium in the metallothionein but not to the amount of metallothionein (protein).