Absorption from gastrointestinal tract of the rat after x-irradiation

¹ Biology Laboratory, Hanford Laboratories, General Electric Company, Richland, Washington

An in situ perfusion method was used to measure glucose absorption from the x-irradiated or nitrogen-mustard-treated rat. Inhibition was greatest 3 days after treatment and recovery had begun by the 6th day. The effect on absorption was not appreciably different after 900 r than after 1,500 r, although histologic damage was much greater after the higher dose. Pretreatment with cysteine or AET prevented the decreased absorption after 900 r but did not protect against 1,500 r nor against the effect of HN₂. The absorption of d(+)-xylose was also decreased 3 days after irradiation of the intestine. Thus, both active and passive transport mechanisms involved in sugar absorption were decreased by irradiation of the intestine. The absorption of fat, on the other hand, was not decreased as a result of direct action by x-radiation on the intestinal epithelium, since oleic acid absorption was unaffected by exposure of the intestine to radiation.