ee ATOMIC MEDICINE gamma radiation on the secretion of adrenal cortical hormones (Rosenfeld et al.). Secretion was markedly reduced; however, it should be noted that the doses used were in excess of 2000 r (somefive times the LDso and always supralethal), and that the isolated organ was removed from secretory stimuli that may be present in the intact animal following acute total body irradiation. Thus, the author’s conclusion that the adrenal cortex must be wine ta oma ae hensHORS ROP O14 considered a radio-responsive tissue cannot be considered to characterize the role of the adrenal in acute total body irradiation. French et al. have demonstrated early changes in plasma hydroxycorticosteroid levels, as well as changes in the peripheral neutrophile, lymphocyte, and eosinophile counts of monkeys givenfrom 50 to 400 r total body radiation. The changes were maximal at 4 to 8 hours, and values were again normal by 12 hours. Shielding of the head or adrenals did not modify these early changes, implying that they were not the result of a direct effect on the pituitaryadrenal axis. Brayer ef al. found, after a supralethal dose of WBR (1000 r)} in swine, that a marked increase in urinary excretion of total adrenal cortical steroids occurred, which was must pronounced in the first 24 hours. In the case of the irradiated animal in the lethal dose range where pancytopenia is followed by its common sequelae of infection and hemorrhage, there is a depletion of the adrenal lipid and by inference one might say that this represents the stage of exhaustion in the adaptation syndrome. The preseat writers are inclined to interpret this terminal state as being simply the reaction of the organism to an overwhelming infection and not primarily to the initial radiation injury. In view of our present knowledge, it appears quite certain that the role of the adrenal cortex is secondaryto the stress of radiation in the development: of the acute radiation syndrome. The previously quoted biochemical changes, the complications of hemorrhage, anemia and infections, the biological complexities of various mammals, and the simultaneous operation of factors which may change electrolyte and water metabolism in opposite directions at the same time point out the hazards that are contingent upon drawing conclusions that adrenal insufficiency exists because some of these changes are observed. The recent review of Savers on the adrenal cortex and homeostasis points out this problem in great clarity. The problem is aiso discussed by Mole. 9.5.7 Pancytopenie Sequelae, Infection. The sequelae of pancytopenia are infection, hemorrhage and anemia. The latter two are discussed in Chapter 8. Infection here will be discussed as it relates to the lethal range of exposure, i1.e., the range where some, butnotall, of those exposed will die within a period of several weeks and to the sublethal range. Evidence that infection is of importance in the acute radiation svndrome falls into several categories: (a) Clinical observations on humanbeings ex- i } i i