Influence of selenium on mercuric chloride cellular uptake and toxicity indicating protection - Studies on cultured K-562 cells

Selenium and mercuric chloride (MC) interactions regarding cellular uptake and selenium protection on MC toxicity have been studied. Human K-562 cells were pretreated or simultaneously treated with either selenite (5 or 50 mu M) or selenomethionine (10 or 50 muM) together with MC (35 or 50 muM). Both treatments with selenite showed an increase of mercury uptake with increas ed selenium dose. In the pretreated or simultaneously treated selenite and 35 muM MC combinations, no inhibition of growth was seen, whereas all 50-mu M MC combinations were toxic to the cells. A selenite-dependent protection was obtained for both exposure protocols when considering the cellular upta ke of mercury. The cells died when the accumulation on d 4 reached more tha n about 0.8 x 10(-15) mol/cell of mercury, whereas they survived up to twof old more mercury uptake when exposed to selenite. Selenomethionine gave, wi th a few exceptions, similar effects as selenite on MC uptake and toxicity