Influence of parital-body x-irradiation on development of phosphorothioate oxidase in the livers of male rats.

Abstract

Recent studies in this laboratory (1) demonstrated that 200 R or 400 R of whole body X-irradiation almost completely inhibits the development of an enzyme in the microsomal fraction (2) of the liver of young male rats that catalyzes the desulfuration of phosphorothioates during the first 3 weeks after exposure. Exposure of partially hepatectomized rats to these doses of X-irradiation also markedly inhibits the synthesis of this enzyme system, whereas exposure of adult rats to X-irradiation has no effect on the enzyme activity. The previous findings indicated that X-ray inhibits the development of an enzyme-synthesizing process rather than altering the activity of phosphorothioate oxidase. The present study was undertaken to obtain information concerning the site of the inhibitory action of X-irradiation on the development of the phosphorothioate oxidase system in the livers of young male rats. The development of this enzyme system is markedly stimulated by androgenic substances (3). Since our previous study (1) indicated that the inhibitory effect of X-irradiation is not a direct result of injury to the testes, the effect of X-ray on other localized areas was investigated. The results of this study demonstrated that sublethal doses of X-ray administered to the head area cause a marked inhibition of development of the system responsible for desulfuration of a phosphorothioate (Guthion) in the livers of young male rats.