Effect of radioprotective aminothiols on the induction and repair of single-strand breaks in the DNA of irradiated mammalian cells.

The effect of cysteamine and 2-mercapto-propionyl-glycine on the induction and repair of single-strand breaks in the DNA of Chinese hamster cells by irradiation in vitro in the presence of oxygen or in anoxia was investigated. The substances protected against the formation of breaks by irradiation both under oxic and anoxic conditions. The substances also exhibited a toxic effect which resulted in degradation of DNA. Cysteamine inhibited the rejoining of breaks after radiation exposure.