THE EFFECTS OF ABDOMINAL IRRADIATION ON INTESTINAL TRANSPORT IN THE RAT AS ASSESSED WITH ISOLATED EPITHELIAL-CELLS

The time course of the effect of exposure to sublethal irradiation on transport of several substrates by the intestine was studied using isolated enterocytes. Rats received a single dose of 6 Gy [grays] to the abdomen, and isolated intestinal epithelial cells were prepared 3, 7 and 14 days later. The ability of the cells to take up D-glucose, L-leucine, and glycyl-L-leucine was assessed using 2.5-min incubation periods and was compared with the uptake in control cells. The protein content of the cells apparently increased after irradiation, and although some of this was the result of increased binding of albumin to the cells there was also a nonspecific increase in most cell proteins. Consequently uptake data were expressed per unit number of cells and not per milligram of cell protein. Comparison of uptake expressed in this way showed that D-glucose and glycyl-L-leucine uptake was elevated 3 days after irradiation while that of L-leucine was unaffected. By 14 days after irradiation the glucose and glycyl-L-leucine uptake had returned to normal but the L-leucine transport was depressed. These data indicate that the effects of irradiation upon substrate transport in the intestines are not uniform and that although the cell population is initially reduced the remaining cells can compensate by increasing their transport capacity.