The mutagenicity and cytotoxicity of selenite, "activated" selenite and selenate for normal and DNA repair-deficient human fibroblasts.

At doses varying from 8 x 10(-5) to 3 x 10(-3) M sodium selenite (Na2SeO3) induced DNA fragmentation, DNA-repair synthesis, chromosome aberrations and a mitotic inhibition in cultured human fibroblasts. The response of DNA repair-deficient xeroderma pigmentosum (XP) fibroblasts to selenite is comparable to that of control cells. Incubation with mouse liver S-9 microsomal fraction increased the capacity of selenite to induce chromosome aberrations, DNA-repair synthesis and a lethal effect. XP cells behaved as control cells when treated with activated selenite. Sodium selenate (Na2SeO4) at doses ranging from 8 x 10(-5) to 3 x 10(-3) M could not be activated by incubating with a S-9 preparation. Selenate had the capacity to induce a small but significant DNA-repair synthesis.