The influence of high dietary zinc on tissue disposition and urinary excretion of cadmium, zinc, copper and iron after repeated parenteral administration of cadmium to rats.

The administration of a high dietary supplement of zinc sulphate (2000 ppm) to rats for 28 days produced no effect upon growth rate of the animals but caused in increased food intake. The supplement had no effect upon the reduction of growth rate caused by the daily injection of cadmium chloride (1.5 mg/kg). Zinc-supplemented animals showed an increased accumulation of zinc in the liver and kidney, plasma zinc levels were significantly increased and there was an elevated excretion of zinc in the urine compared to control animals. Cadmium-treated, zinc-supplemented animals had a higher concentration of cadmium in the liver compared to animals treated only with cadmium. The high dietary zinc did not interfere with tissue or plasma concentration of copper and iron, nor did it influence the cadmium-induced changes in these metals. There was some indication however of a decreased urinary excretion of copper.