990 RADIATION BIOLOGY 



ent lack of specificity of radiation injury raise the question of the place 

 of the adrenal in the development of, and recovery from, the acute 

 radiation syndrome. 



The suggestion that clinical radiation sickness reflects adrenal cortical 

 damage has been made by a number of investigators, who were either 

 impressed with the similarity between the symptoms of radiation sickness 

 and those of adrenal cortical insufficiency or with the efficacy of adrenal 

 preparations in alleviating the discomfort sometimes associated with 

 therapeutic irradiation (Narat, 1922; Hirsch, 1923; Thaddea, 1940; 

 Weichert, 1942; Ellinger, 1948). As early as 1924, however, Martin and 

 his associates were unable to detect functional changes in dogs from which 

 one adrenal was removed and the other irradiated with a dosage sufficient 

 to cause fibrotic changes. When the same dosage of X rays was applied 

 to an isolated loop of small intestine, cachexia and death resulted. Later 

 Fisher et al. (1928), employing a similar technique, observed signs of 

 adrenal insufficiency in a dog but only after heavy irradiation and a 

 latent period of about three months. 



It appears, from morphological studies, that the adrenals are not 

 peculiarly radiosensitive (Frey, 1928; Desjardins, 1928; Engelstad, 1936; 

 Engelstad and Torgersen, 1937; Torgersen, 1940; Rhoades, 1948b). 

 Although degenerative changes have been seen after heavy local irradia- 

 tion (above 1500 r), dosages of 1000 r result only in minimal morpho- 

 logical alteration in the adrenal cortex and medulla (Engelstad, 1936; 

 Engelstad and Torgersen, 1937). Notwithstanding the apparent resist- 

 ance of the adrenals to structural change, functional responses may be 

 elicited with relatively low dosages. Loss of adrenal cortical lipids and 

 adrenal ascorbate occurs soon after irradiation, and urinary excretion of 

 the 17-ketosteroids may be increased several days later (Dougherty and 

 White, 1946; Patt et al, 1947; Nizet et al., 1949; North and Nims, 1949; 

 G. H. Lawrence, 1949). Lipid depletion has also been noted in some of 

 the victims of radiation exposure in Japan (Shields Warren, 1946). The 

 pattern of adrenal response in X-rayed rats consists of an initial reduction 

 in adrenal cholesterol, a normal or elevated cholesterol concentration 

 associated with adrenal hypertrophy several days later, and a marked 

 terminal depression (Patt et al., 1947). The adrenal response does not 

 occur in hypophysectomized animals and can be prevented, in part, by 

 suitable administration of adrenal cortical extract (Patt et al., 1948; 

 Swift et al., 1948). In contrast to the changes in adrenal lipids, oxidative 

 capacity of adrenal slices obtained from irradiated rats is not altered 

 appreciably (Barron, 1946). 



The changes in adrenal lipids after irradiation probably reflect an 

 increased demand for cortical secretions, which may perhaps be satisfied 

 initially but not terminally. It is noteworthy that a single injection of 

 adrenocorticotrophic hormone decreases adrenal cholesterol in normal 



