Effect of 2-β-Aminoethylisothiourea (AET) against Genetic Damages Induced by X-Irradiation of Male Mice

Abstract

Since the radioprotective properties of 2-mercaptoethylamine (MEA) (1) and 2,B-aminoethylisothiourea (AET) (2) became known, many studies have been carried out on the effects of sulfhydryl and related compounds on irradiated germ cells. Thus, Rugh and Wolff (3) found in 1957 that cysteamine decreases the sterilizing effect of X-rays in female mice, and injection of cysteamine before irradiation has a protective effect on the male germ cells of mice (4) and rats (5). In contrast to the studies of Kaplan and Lyon (6), recent results of Liuning et al. (7) indicate that injection of cysteamine reduces the postimplantation death induced by irradiation of spermatozoa by about 25 %. Disappearance of male germ cells after irradiation is slower and their regeneration is faster in animals receiving 2-,3-aminoethylisothiourea (AET) before X-irradiation than in those without treatment (8), and protection of the reproductive capacity after injection of AET has also been observed in X-irradiated female rats (9). On the other hand, the yield of recessive and dominant lethal mutations in Drosophila increases about 10 to 15 % if AET is administered prior to irradiation, whereas it remains unchanged if it is given after the exposure (10). Similar results were found in Neurospora (11). Since no data on the radioprotective action of AET on dominant lethal mutations in mice are as yet available, this problem has now been studied in more detail. The male germ cells of mice react in a different manner depending on whether they are in the postmeiotic or premeiotic stage; therefore spermatozoa, spermatids, and spermatogonia were investigated separately by choosing for the mating different time intervals after irradiation.