The effect of lead on protein and DNA metabolism of normal and lead-adapted rat kidney cells in culture.

Cultures of epithelial rat kidney cells were used to investigate the effect of lead on protein and DNA metabolism. Lead-adapted cells were cultured in 5 and 10 microM Pb(NO3)2 for several months and subsequently showed the same growth characteristics but a higher resistance to increased lead doses than untreated cells. Both normal and adapted cell types were exposed to lead nitrate in concentrations from 5 to 1000 microM for incubation periods of from 1 to 24 h. 3H-leucine incorporation was increased in 10 microM lead by up to 140% in normal but not in adapted cells, pointing to a resistance forming mechanism. Not only is the overall rate of protein synthesis increased, but separations of cytosolic proteins by SDS-polyacrylamide electrophoresis indicate the novel or increased synthesis of several proteins. A difference could also be observed in the DNA metabolism, where normal cells show a very pronounced increase of up to 900% after 24 h of incubation. This was not observed in adapted cells.