Development of intestinal damage after x-irradiation and H3-thymidine incorporation into intestinal epithelial cells of irradiated goldfish, Carassius auratus, at different temperatures.

In laboratory rodents, much significance has been attached to changes in cell population of the intestinal epithelium in relation to the so-called intestinal death after X-irradiation (1). In teleost fish also, on the basis of a series of experiments designed to study relationship between dose of irradiation and causes leading to radiation death, it has been suggested that intestinal damage might be largely responsible for death after irradiation with doses of the dose-independent range (4 to 32 kR) (2-4). Furthermore, the present author has shown that, in goldfish maintained at 22?C after X-irradiation, acute radiation death preceded by intestinal damage invariably occurs (4), whereas in those placed in cool thermal surroundings neither acute radiation death nor histological damage in the intestinal epithelium takes place at least within 100 days (5). In order to analyze in more detail the relation between survival time of irradiated fish and rate of cell renewal in the intestinal epithelium, mortality rate of irradiated goldfish, histological changes in the intestinal epithelium, and rate of thymidine uptake by epithelial cells during a period of 200 days after irradiation were studied at different temperatures.