Regulation of glutathione S-transferase gene expression and activity by dietary selenium

To determine selenium's effects on glutathione S-transferase gene expression and enzyme activity, weanling rats were fed a selenium-deficient diet, or the same diet supplemented with 0.1 (control) or 2.0 mg selenium/kg diet as sodium selenite, for 91 days. Consumption of either the selenium-deficient or high selenium diet increased activity of glutathione S-transferase, measured with 1-chloro-2,4-dinitrobenzene as substrate, compared to the control diet. Transcription of genes for glutathione S-transferase subunits was unaffected by selenium intake. Steady state levels of mRNA for glutathione S-transferase subunits were affected variably by changes in selenium intake, depending upon the tissue and subunit examined. These results suggest that the biological effects of selenium may be due in part to its regulation of gene expression for glutathione S-transferase family enzymes.