The protective effect of intra-arterial vasopressin injections on the small bowel during fractionated abdominal irradiation. A study in pigs.

The radioprotective effect of vasopressin-induced intestinal ischemia was investigated in pigs. A bolus injection in the cranial mesenteric artery, of a vasopressin solution, 0.05 IU/kg body weight, was followed by irradiation of the small intestine with 6 MV roentgen rays. Three different fraction schedules were used. Weight changes in the animals and the histologic appearance of their intestines were recorded two weeks after irradiation and compared with the findings in untreated animals. Intra-arterial vasopressin was very effective in protecting the intestine. Vasopressin treatment given before 2 fractions with relatively high radiation doses in a 6-fraction regimen was so effective that it may form the basis of a treatment model applicable in man.