Radioprotective and radiosensitizing effects of sulfur-containing amino acid derivatives on mice.

Both protection and sensitization of Mice C57Bl against 60Co gamma-rays by sulfur-containing amino acid derivatives--S-alkyl-L-cysteines, S-alkyl-2-methyl-DL-cysteines and their hydantoin derivatives, and sulfoxides of these compounds--were examined. DL-5 Allylthiomethyl-5-methylhydantoin (150 mg/kg body weight) had a remarkable radioprotective effect. The survival ratio was 4.3 or above two times as much as that of L-cysteine. On the other hand, its sulfoxide had a radiosensitizing effects; survival ratio, 0.333.