Modification of the action of misonidazole. III. The effect of diamide on toxicity and radiosensitization.

Diamide, a compound which depletes cells of reduced glutathione, decreases toxicity of misonidazole to hypoxic cells, as measured by single-strand break (SSB) production, cell inactivation, and uptake of radioactive misonidazole. As a radiosensitizer, the effect of diamide in cell pellets is additive to that of misonidazole. Individually, both misonidazole and diamide enhance SSB production in DNA of cells irradiated under hypoxia in dilute suspension, but a combination of the two drugs does not appear to produce a greater number of SSB than misonidazole alone.