STATE OF IRON REPLETION AND CADMIUM TISSUE ACCUMULATION AS A FUNCTIONOF GROWTH IN YOUNG-RATS AFTER ORAL CADMIUM EXPOSURE

To check the hypothesis that adequate dietary iron supplementation red uces cadmium retention and cadmium-induced anaemia during fast growth, three different dietary iron concentrations (6 mg/kg = iron-deficient ; 55 mg/kg = marginal iron supply; 180 mg/kg = luxurious iron supply) were offered to growing rats. Four groups of rats at different age (44 days not similar to 150 +/- 6 g, 49 days +/- 180 congruent to 3 g, 57 days congruent to 220 +/- 4 g, and 84 days congruent to 295 +/- 9 g) received a diet with 55 mg Fe/kg which is a marginal iron-supply durin g growth. Six animals in each age group were exposed to 10 mg Cd/l as CdCl2 in the drinking water for 1 week; six animals in each age group received no cadmium. In the youngest and oldest groups additional 6 an imals were exposed to the same cadmium dose but received an iron-defic ient (6 mg Fe/kg) and an iron-adequate diet (180 mg Fe/kg) together wi th corresponding controls. The state of iron repletion was monitored b y the tissue iron content in liver, kidney, and duodenum as well as by the concentrations of haemoglobin, plasma iron and plasma transferrin . The youngest animals showed the highest percent weight increases. Ca dmium administration influenced neither growth rates nor food and wate r intake. At a dietary iron content of 55 mg/kg, iron repletion was ne gatively correlated to growth while the cadmium content in liver and k idney showed a positive correlation. At fast growth, a dietary iron co ntent of 6 mg/kg lead to iron-deficiency anaemia and high cadmium rete ntion. At all dietary iron concentrations, cadmium retention as well a s the cadmium-related reduction in haemoglobin concentration was signi ficantly higher at fast growth. Adequate dietary iron supplementation reduced cadmium retention and cadmium-induced anaemia significantly. T hus, the delicate balance between iron supply and the increased iron d emand during growth can be disturbed within one week by a daily cadmiu m intake as low as 0.7-1.3 mg Cd/kg body weight.