The Pharmacological Effects of Some Radioprotective Agents in Mice

Abstract

Compounds suspected of having the ability to protect animals against the lethal effects of ionizing radiation are usually tested in mice. Among the most successful compounds tested thus far are 2-aminoethylisothiuronium bromide hydrobromide (AET), mercaptoethylamine (MEA), 3-aminopropylisothiuronium bromide hydrobromide (APT), and 3-aminopropyl-N'-methylisothiuronium bromide hydrobromide (APMT). When administered prior to a certainly lethal dose of X-irradiation (800 r), these compounds afford mice complete protection. The protectant activity is thought to result from the presence of sulfhydryl groups which behave as radical traps, thus sparing the animal from the harmful effects of free radicals formed on the irradiation of body water (1). Because of the importance of compounds which protect against radiation, it is necessary to understand the pharmacological responses of these agents in mammals. To date, the animal of choice for the pharmacological testing of radioprotective compounds has been the cat (2-5). In these studies, evidence of low toxicity was sought, but also, of theoretical interest, an attempt was made to correlate the pharmacological effects and the ability to protect against the lethal effects of radiation. Obviously it was difficult to make a meaningful generalization from one species to the other, from the pharmacological responses in the cat to the radiation protection in the mouse; consequently, techniques were developed to permit the investigation of pharmacological properties of radioprotective agents in mice. This paper describes these techniques and the comparison of pharmacological responses of mice with those already observed of cats. METHODS