Cell Population Studies on the Intestine of Continuously Irradiated Rats

Rats were exposed for 5 days to doses of 84, 176, and 415 rads/day gamma radiation. Intestinal injury was determined by examination of whole-crypt squashes for total cell population, the number of cells in mitoses, and the number of cells labeled with H/sup 3/-thymidine after a single injection. An increase in the incorporation of H/sup 3/-thymidine into the nuclei of the intestinal epithelium was observed after exposure to 415 rads/day. (C.H.)