Arsenic uptake, cytotoxicity and detoxification studied in mammalian cells in culture.

The cytotoxicity of trivalent and pentavalent inorganic arsenic salts was determined in mouse fibroblasts in vitro. Concentrations of As (III) in the microM range led to a reduction of proliferation and viability with a concomitant increase in LDH release and stimulation of lactic acid production. Similar effects were noted with approximately 10-fold greater molar concentrations of As(V). Cells pretreated with a low As(III) concentration are less sensitive to toxic doses of As(III) or As(V). Uptake of As(III) by the fibroblasts is greater than that of As(V). Both forms of inorganic arsenic are converted intracellularly to monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are then released into the culture medium. In As-pretreated cells, which are more resistant to As toxicity, biotransformation of inorganic arsenic to MMA and DMA is increased.