Adriamycin (ADR) is a potent anticancer drug that causes often severe cardiomyopathy. Previous reports have demonstrated that zinc accumulation is shown in rat myocardial cells following ADR treatment. However, the mechanism and role of zinc accumulation in ADR-induced cardiomyopathy are not yet elucidated. Zinc may be one of the key executors in ADR-induced cardiomyopathy. To test this hypothesis, we examined the cytotoxic effects of zinc on various cell lines including H9c2 cardiomyoblast cells, HL-60, U937, and C(6)-glial cells. Zinc induced significant the death of H9c2 cells at 0.125 mM in a dose-dependent manner. However, zinc did not induce any cytotoxic effect on both promyelocytic leukemic HL-60 cells and monoblastoid U937 cells. The nuclear morphology of Zn(2+)-treated H9c2 cells displayed apparent chromatin condensation, but no formation of chromatin fragmentation. In addition, phosphatidylserine (PS) externalization was observed by annexin-V staining. Zinc markedly decreased the intracellular GSH level in a time-dependent manner. Exposure to 0.2 mM ZnCl(2) for 6 hr decreased the intracellular GSH content to 13% of control value. Zinc-induced death of H9c2 cells and the intracellular GSH depletion were completely prevented by the addition of exogenous GSH and NAC. These result suggests that intracellular GSH depletion is directly involved in zinc-induced cardiomyopathy.