Fig. 2.

Effect of selenium on doxorubicin-enhanced reactive oxygen production. (A) Parental cardiac fibroblasts with or without selenium supplementation. Only the lower two panels represent experiments in which selenium has been added to the cell cultures. High glutathione peroxidase activity levels in selenium supplemented parental fibroblasts almost completely block doxorubicin-enhanced reactive oxygen formation (right middle versus right lower panel). (B) Gpx-1 knockout cardiac fibroblasts demonstrate no effect of selenium supplementation on doxorubicin-enhanced reactive oxygen formation for two different drug concentrations (middle versus lower panels). As is the case in (A), the top and middle panels represent experiments performed for fibroblasts without added selenium (Se-cells). These data are representative of at least three separate experiments.