Cytotoxicity of alkylating agents in isolated rat kidney proximal tubular and distal tubular cells.

Patterns of chemical-induced cytotoxicity in different regions of the nephron were studied with freshly isolated proximal tubular and distal tubular cells from rat kidney. Three model alkylating agents, methyl vinyl ketone, allyl alcohol, and N-dimethylnitrosamine, were used as test chemicals. Methyl vinyl ketone and a metabolite of allyl alcohol, acrolein, are Michael acceptors that bind to cellular protein sulfhydryl groups and GSH. N-Dimethylnitrosamine binds to cellular protein and DNA. Lactate dehydrogenase leakage was used to assess irreversible cellular injury. Distal tubular cells were more susceptible than proximal tubular cells to injury produced by methyl vinyl ketone or allyl alcohol while the two cell populations were equally susceptible to injury produced by N-dimethylnitrosamine. Preincubation of both proximal tubular and distal tubular cells with GSH protected them from methyl vinyl ketone- and allyl alcohol-induced cytotoxicity but had no effect on N-dimethylnitrosamine-induced cytotoxicity. Similarly, incubation of cells with methyl vinyl ketone or allyl alcohol, but not N-dimethylnitrosamine, altered cellular GSH status. As with GSH status, incubation of cells with methyl vinyl ketone or allyl alcohol, but not N-dimethylnitrosamine, caused pronounced inhibitory effects on mitochondrial function, as evidenced by ATP depletion and inhibition of cellular oxygen consumption. These results demonstrate that alkylating agents are cytotoxic to both proximal tubular and distal tubular cells, and that interaction with cellular GSH is a factor determining nephron cell type specificity of injury.