Abstract: Researchers determined how oxidative stress induced by excess Se alters expression of selected selenoproteins in the jejunum from mice fed diets of different Se content. Deficient Se diet downregulated the mRNA level of GPx1, GPx4 and SEPW1; super nutrition Se dramatically increased the level of GPx1 and SEPW1 mRNA levels but had no effect on GPx2 mRNA level. The excess Se diet led to decrease GPx1 and SEPW1 mRNA levels but had little effect on the level of GPx4 mRNA. The data show that mRNA levels of the GPx family or selenoprotein W are differentially regulated by dietary Se.