URINARY-EXCRETION OF IOHEXOL AFTER ENTERAL ADMINISTRATION IN RATS WITH RADIATION-INJURY OF THE SMALL-INTESTINE

Gut membrane dysfunction after acute and subacute irradiation injury to 10-cm-long small-bowel segments was assessed in 85 rats receiving doses of 17 and 21 Gy. Four and 14 days after irradiation 2 ml iohexol was administered via orogastric tubes, and hourly radiographs were taken. After 8 h, blood and urine were sampled for testing, and the intestine biopsied for light and scanning electron microscopy. Dense opacification of the urinary bladder was seen on abdominal films, and increased serum and urinary levels of iodine were demonstrated by X-ray fluorescence analysis in irradiated animals. Urinary levels were up to 20 times higher than in controls 4 days after irradiation, subsiding after 14 days. The effects were prolonged in the 21-Gy group. Our results indicate that measurement of iodine levels in serum and urine may be helpful in assessment of bowel injury in the course of irradiation treatment to pelvic or abdominal organs.