Acute X-Ray Lethality in the Chinese Hamster after Whole-Body and Partial-Body Irradiation

Abstract

Acute radiation lethality was studied in the Chinese hamster, Cricetulus griseus, during the 100-day period after whole-body and partial-body exposure to 250-kvcp x rays. The results indicate this species to be one of the most re sistant mammals thus far studied. After whole-body exposure, the dose-effect curve was best determined on day 40 in the male and on day 100 in the female. During 1959 to 1960, prior to the fifteenth inbred generation, the LD₅₀ values were: male, 856 rads, and female, 784 rads. During 196l, additional determinations for the males of the fifteenth through the seventeenth inbred generations indicated the LD₅₀ to be over 900 rads. Pentobarbital anesthesia (60 mg/kg, i.p.), may increase the LD/sub 50/ by about 5%. During 1961, the pooled male and female data for posterior-body exposure under pentobarbital anesthesia showed the doseeffect curves on days 28 and 100 to be alike: LD₅₀ = 1297 rads. The analogous data for anterior-body exposure indicated two modes of death, a rapidly acting one, estimated from the deaths occurring within a month of exposure, and a slowly acting one, which killed during the interval 40 to 100 days. (auth)