Essential metals and metallothionein in cadmium-induced thymic atrophy and splenomegaly

Cadmium chloride was injected intraperitoneally into mice and the animals were sacrificed 1, 3, and 9 days after the injection. The concentrations and contents of cadmium and six essential metals in the thymus, spleen, kidney, and liver were determined by inductively coupled plasma-atomic emission spectrometry. Although the accumulation of cadmium in the thymus and spleen was as low as 0.05 and 0.2–0.4% of the injected dose, respectively, compared to liver (60%) and kidney (6.5–9.0%), the two immune organs showed dramatic changes of weights; namely severe atrophy of thymus and enlargement of spleen. The concentrations of zinc in the two immune organs did not change during the atrophy or enlargement, though the contents showed significant decrease or increase dependent upon the changes in weights. The concentrations and/or contents of other essential metals also changed with time and the changes depended on organs. The distributions of cadmium in the supernatant fractions of thymus and spleen were determined by high speed liquid chromatography with a flame atomic absorption spectrophotometer. Two cadmium peaks which correspond to the two isometallo-thioneins were eluted exactly at the same retention times as those of liver metallothioneins.