Influence of Dietary Cadmium on the Distribution of the Essential Metals Copper, Zinc and Iron in Tissues of the Rat

The effect of long-term dietary cadmium treatment upon the distribution of the metals copper, iron and zinc has been compared in various organs of male and female rats. The renal accumulation of cadmium was similar in both sexes without a plateau being reached. In contrast, the hepatic accumulation of cadmium was higher in the female than in the male rat and a plateau was observed after 30-35 weeks of dietary cadmium treatment. Most of the cadmium which accumulated in these organs was recovered in the metallothionein fraction andthe concentration of hepatic cadmiumthionein in the female rat was correspondingly higher than in the male rat. Accumulation of cadmium was associated with an increased zinc concentration in the liver and an increased copper concentration in the kidney; these increases were correlated with increases in liver and kidney metallothioneins induced by cadmium. Uptake of cadmium into organs other than liver and kidney occurred to a small extent but was not associated with changes in the concentration of copper and zinc. Cadmium also accumulated in the intestinal mucosa where it could be recovered in a fraction corresponding to metallothionien. A loss of iron from the liver and kidney was also observed following dietary cadmium treatment and involved mainly a loss of iron from ferritin.