Intraluminal, lymph node, hepatic, and serum levels after intraluminal and intramural injection of 5-fluorouracil in the dog colon.

The tissue levels of 2-14C 5-fluorouracil were compared after three routes of administration in the colon of fifteen dogs. "Simple" submucosal injection resulted in higher levels in the colonic wall, abdominal lymph nodes, and liver than did rapid intravenous injection. Intraluminal administration demonstrated that the appearance of 5-FU was prompt and that significantly higher levels continued in the colonic wall and liver, but nodal levels were markedly lower.