The effect of graded doses of cadmium on lead, zinc and copper content of target and indicator organs in rats

Eleven groups of inbred Wistar rats, five males and five females in each group, received graded doses of CdCl₂, from 0–25 ppm, in the drinking water from conception until sacrifice at the age of ten weeks. The Pb, Zn and Cu levels of various indicators and target organs were recorded by atomic absorption spectrophotometry. Cd concentrations above 5 ppm caused a significant increase in Zn content of kidneys, liver, spleen, heart and adrenal glands in most of the experimental groups, and in addition a significant positive correlation between Cd and Zn in the same tissues. With concentrations above 10 ppm, Zn contents of epiphyses and diaphyses decreased significantly, and through all groups there was a significant negative correlation between Zn and Cd in diaphysis. This local Zn deficit may cause a retarded growth of long bones. Cd supply resulted in a significant decrease in Zn content of incisors and molars, but did not significantly affect the Cu content. Neither were Zn nor Cu concentrations in hair affected. Cd supply led to a significantly increased storage of Cu in liver, spleen, heart and skeletal muscle and a positive correlation between Cd and Cu content in the same tissues. Cd administration caused a significant decrease of Pb concentrations in molars, hair, kidney cortex, heart, skeletal muscle and adrenal glands in several of the experimental groups, and also a significant negative correlation between Pb and Cd content of molars, hair, kidney cortex, liver and heart. This can be a result of decreased uptake, increased excretion or changes in the distribution pattern of Pb.