Impaired oxidation of pyruvate in human embryonic fibroblasts after exposure to L-dopa.

The effect of 3,4-dihydroxyphenylalanine (L-dopa) treatment on the ability of intact human cells to metabolize substrates for mitochondrial oxidative phosphorylation was studied in embryonic fibroblasts. Treatment with L-dopa (100-400 microM) for 48 h significantly reduced the oxidation of pyruvate but had no effect on succinate oxidation. The effect was dose-dependent and was still present 2 days after removal of L-dopa. Ascorbic acid (200 microM) protected the cells from the effects of L-dopa; ascorbate alone enhanced pyruvate but not succinate oxidation.