Effect of erythropoiesis on splenic cadmium-metallothionein level following an injection of CdCl2 in mice.

The effects of erythropoiesis on cadmium-metallothionein (Cd-MT)2 levels in spleen, a major erythropoietic tissue, was examined following sc injection of 109CdCl2 into mice. As the concentration of Cd in plasma decreased following injection of 109CdCl2 into control mice, the levels in spleen and liver increased rapidly. After 48 hr, when the concentration of Cd in the erythrocyte (RBC) was at maximum, the level of Cd in the spleen, but not liver, had decreased. These variations of Cd concentration in spleen and RBC were more notable in mice made anemic by phenylhydrazine (PH). Zinc (Zn)-MT was detected in the PH-induced hemopoietic spleen. A subsequent injection of CdCl2 further induced Cd-MT in the spleen. The protein in spleen contained Cd and Zn but not Cu as in RBCs. Maximum levels of Cd-MT in spleen and RBCs of the PH-treated mice were about four times higher than those of control mice. The concentration of Cd-MT in the spleen of polyemia mice, induced by RBC transfusion, was 50% lower than that of control mice. When erythropoietin was injected into the polyemia mice prior to CdCl2, the concentration of Cd-MT in spleen increased about sixfold. These changes in Cd-MT levels in spleen were not observed in either liver or kidney. The effects of erythropoiesis on the concentration of Cd-MT in the spleen corresponded with effects seen in RBC. These results suggest that splenic Cd-MT can be the source of Cd-MT in mature RBC.