Structure-Function Studies of the Aminothiol Radioprotectants. Effect of Carbon Chain Length in Mercaptoethylamine Homologs: Mammalian Radioprotection

The relation between chemical structure and radiation protection in mice has been studied for a series of aminothiols. The aminothiols used in this study were β-mercaptoethylamine (MEA) and its propyl, butyl, pentyl, and hexyl homologs. Mice were given equimolar quantities of these drugs 15 minutes before gamma irradiation at their ${\rm LD}_{70(30)}$ (875 rads). At the radiation and drug doses employed, only MEA showed a radioprotective effect. This result is in marked contrast to those of previous studies in bacteria where pharmacological effects were avoided and only physical-chemical effects were studied.