Uptake of metal cations by fibroblasts in vitro

Abstract

Atomic absorption spectroscopy was used to assess uptake of Ag⁺¹, Au⁺⁴, Cd⁺², Cu⁺², In⁺³, Ni⁺², Pd⁺², and Zn⁺² 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 Pd⁺² 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⁺² increased over the same period. The tendency of the cells to accumulate these cations correlated with their cytotoxic potency (measured previously). © 1993 John Wiley & Sons, Inc.