Effects of Zinc in the Synthesis of Cadmium Binding Protein in Cadmium-treated Female Rats : The Relationship between Cadmium Binding Protein Concentration and Cadmium-induced Liver Damage

Sixty female rats were divided into 4 groups. The diet for group I was supplemented with 200 pg Cd per g diet and that for group II was supple-mented with 200 pg Zn per g diet and to the diet for group III were added 200 pg Cd and 200 pg Zn per g diet. Group IV was the control group fed normal diet. They were sacrificed at 11th, 26th and 40th week of exposure. Cd content in the liver of the rats exposed to Cd alone (group I) was higher than that of the rats exposed to Cd-F Zn (group III) at 26th and 40th week of exposure. Metallo-thionein (MT) concentration in the rats of group I was consistently higher than that of group III. At 40th week of exposure, MT fraction in the sephadex G-75 elution profile of group I showed a definite shoulder and this shoulder was not observed in the rats of group III. Pathological changes were observed in the liver of group I but not in group III. Present results suggest that the formation of additional molecular species of Cd containing protein is associated with Cd-induced hepatic damage.