Influence of Rat Blood on Radiation Protection of Mammalian Cells by Cysteamine and Cystamine in Vitro

Summary The protective effect of cystamine and cystamine on T-cells in normal growth-medium was studied in the presence of whole rate blood (WRB). The protective effectiveness of both agents was increased by the addition of WRB, but much less so on the activity of cystamine. In the presence of WRB a dose-reduction factor of 1·5 was obtained at the low concentration of 0·05 mM cysteamine. The increase in protection was not due to induction of anoxia or to a release of glutathione from the rat red cell. The increase in protection may be due to protector RS· radicals reacting with rat red cells.