Effects of Acute Whole-Body X-Irradiation on the Absorption and Distribution of Na22 and H3OH From the Gastrointestinal Tract of the Fasted Rat

Abstract

The rate of absorption of Na22 administered into the stomach of the rat was decreased markedly by an LD50 of X-irradiation. The effect was present at 24 hours, marked at 48 hours and returned toward normal at 96 hours after exposure. Stomach emptying was delayed but transport of Na at intestinal mucosa was the rate limiting factor. Rate studies of the movement of Na22 and H3OH into and out of the small intestine of the rat 48 hours after a supralethal irradiation (2000 r) revealed striking changes in kinetics of active transport. In irradiated animals the net movement was from blood to gut. The composition of fluids apparently moving in each direction was also greatly altered. The wet weight of liver 48 hours after an LD50 was increased 16%. The Na22 space of liver was slightly decreased and the intracellular water greatly expanded.