5-Aminolevulinic acid (ALA)-generated oxyradicals are known to cause oxidative lesions in cells. We studied the effect of the added ALA on the expression of classical cellular glutathione peroxidase (GSHPx-1), catalase and inducible heme oxygenase (HO-1) genes in murine erythroleukemia (MEL) cells. We measured the level of labelled specific mRNAs after (5, 6-3H) uridine incorporation into cellular RNAs, isolation of cytoplasmic RNA and its hybridization with unlabelled cDNA filters. ALA prooxidant activity was studied in the presence of complex of iron with pyridoxal isonicotinoyl hydrazone as an iron donor or in the presence of iron chelators, desferrioxamine (DFO) or 1, 10-phenanthroline (o-Phe). Incubations of cells were done in dark to prevent the oxidative stress by the illumination of endogenous photosensitizers, porphyrins, synthesized from the added ALA. ALA-mediated oxidative stress in the presence of iron enhanced GSHPx-1, catalase and HO-1 genes expression in both uninduced and to erythroid differentiation induced MEL cells of line 707. DFO and o-Phe decreased the effect of ALA. The similar results were obtained in Fw variant of heme deficient MEL cells noninducible for hemoglobin synthesis.

Keywords: murine erythroleukemia cells, Iron, catalase mRNA, glutathione peroxidase mRNA, 5-aminolevulinic acid