Effect of acute and subchronic exposure to cadmium on the retention of iron in rats.

The influence of cadmium on the retention of a single dose of iron after acute and subchronic treatment with cadmium was studied in normal rats. Additionally the results were compared with iron retention in unexposed iron-deficient animals. Test solutions contained iron and cadmium in various molar ratios (Fe:Cd = 1:0, 1:0.5, 1:1, 1:2 mumol/kg body weight). In acute experiments iron retention of normal unexposed rats was decreased in a dose-dependent manner by cadmium. In subchronic studies the diets fed during the treatment period contained iron (28 ppm) and cadmium (28, 56, 112 ppm) in the same molar ratios as did the test solutions. After 4 weeks of feeding a cadmium-fortified diet, the retention of a single dose of 59Fe was increased in all pretreated animals. Iron retention of the cadmium-fed rats was reduced, however, only if cadmium and iron were administered simultaneously. Cadmium appears to compete with iron at the iron transfer system. Acute or subchronic exposure to cadmium did not appear to influence the capability of the intestine to adapt absorption of iron to the increased requirement of the organism or to the utilization of iron for hemoglobin synthesis.