Dependence of Radioprotective Effect of Chemical Modifying Agents on Their Intracellular Concentrations

Summary

Regularities of the radioprotective effect of chemical modifying agents cysteamine, caffeine benzoate, thioglycolic acid, and caffeine, all weak electrolytes, have been studied in cultured Chinese hamster cells. Efficiency of protection is shown to be dependent on pH and concentrations of the drug inside the cells and in the medium. Based on the theory of the dissociation of weak electrolytes and their distribution between the cells and the medium a strong correlation between the efficiency of modification of the radiation response and intracellular concentration of a modifying agent is shown.