Uptake of metal cations by fibroblasts ilz nitro

Atomic absorption spectroscopy was used to assess uptake of Ag+l, A u + ~ , Cd+2, CU’~, In+3, Ni+2, Pd+’, and Zn+’ by in vitro cultures of Balb/c 3T3 fibroblasts as a function of concentration of the cations in cell-culture medium. Reversibility of this uptake was also measured. Metal cations exhibited a 400-fold difference in their tendency to accumulate in the cells; In+3 tended to accumulate the most, whereas accumulated the least. Uptake of the cations in the cells increased linearly with the concentration of the cation in the medium for all cations up to their 50% toxicity concentrations. Reversal of this uptake was slower than that of the initial uptake for three cations studied in more detail (Cd+2, In+3, and Ni+2). The duration of the initial exposure affected the proportion of the metal cations that were retained by the cells 5 h after the cations were removed from the medium. The proportion of retained Cd+2 did not change when the initial exposure was increased from 2 h to 6 h, whereas the proportion of retained In+3 decreased and Ni” increased over the same period. The tendency of the cells to accumulate these cations correlated with their cytotoxic potency (measured previously).