Whole-Body Irradiation and Active Transport in the Rat Small Intestine in Vitro

Large doses of ionizing radiation produce delay in gastric emptying and a reduction in intestinal epithelial cell numbers, and both these changes could produce the reduction in the total transport capacity of the small intestine reported by many workers (1-10). However, along with these gross changes, the functional capacity of the remaining individual cells themselves might also be affected. Perris et al. (11) showed that 3 days after irradiation the capacity of the jejunum to transport fluid and glucose in vitro was diminished, while oxygen uptake was unaffected. In the ileum, on the other hand, only fluid transfer was affected, and the response was maximal on the second day after irradiation. Under the particular experimental conditions of Perris et al. (11), active sodium ion movement (12) was necessary for fluid transport, and glucose transfer in the jejunum occurred against a concentration gradient. Whole-body irradiation may thus depress all active transport processes. This paper is an attempt to study the possibility further.