Distribution and Excretion of Electrolytes after Acute Whole-Body Irradiation Injury. II. Studies with Radiosodium.

Abstract

Following acute whole-body irradiation at an LD50 level to adult male rats, with the onset of post-irradiation diarrhea there is a 10-fold increase in fecal concn. of Na22 and a homeostatic decrease in urinary concn. As diarrhea subsides urinary Na22 concns. increase above the control levels. Tissue analyses for Na22 concn. reveal an initial decrease followed by an increase in the gastrointestinal tract and a more transient decrease with a subsequent striking increase in the lymph nodes. Gastrointestinal tract, testes, and liver show an initial increase in water content which gradually decreases. All organs show a rise in water content on the 9th day. Radiosensitive tissues show a sharp decrease in dry wt. The initial loss of Na22 from several tissues may be associated with the formation of osmotically active radicals in injured cells. The prompt defense of Na by the kidney in the face of Na-rich diarrhea suggests the maintenance of functional integrity of the kidney after heavy doses of irradiation.