Cells with reduced glutathione level that also lack MTF-1 are hypersensitive to cadmium. The viability of cells was assessed with the so-called MTT assay. Mouse embryonic fibroblasts with (ckoC) and without (delC19, delC21 and delC23) functional Mtf1 were compared. Cells were pre-incubated in medium containing 0, 5, 10, 25 or 50 µM BSO for 24 h and further exposed to 0, 5, 10 or 20 µM CdCl2 (Cd) in the specified pre-incubation medium for an additional 24 h. Results are expressed as mean values ± SD (n = 3) normalized to the respective value of untreated cells.