Alterations in the Survival of X-irradiated Cells by 2, 4-dinitrophenol Depending on ATP Deprivation

Summary

The dose—survival curve of cultured melanoma cells was changed by post-irradiation treatment with 2,4-dinitrophenol (DNP). The parameters of the curves were D₀ = 147 R and n = 5·6 for untreated cells and D₀ = 143 R, n = 7·9 and D₀ = 142 R, n = 2·0 for the cells treated with 10⁻⁵ M DNP and 5 × 10⁻⁵ M DNP in phosphate-buffered saline, respectively. The content of ATP in the cell decreased to 5 per cent of the control level after treatment with either concentration of DNP. The recovery of ATP content was rapid and complete after 2 hours' incubation in culture medium after the removal of 10⁻⁵ M DNP, but was retarded and incomplete after 4 hours with 5 × 10⁻⁵ M DNP. Thus prolonged ATP deprivation with a high concentration of DNP results in an inhibition of recovery and a reduction in the n-value.