Effect of transient intestinal ischaemia on the thoracic duct lymph absorption of endotoxin.

One-hour intestinal ischaemia by clamping the superior mesenteric artery and interrupting the intramural collaterals was produced in 8 dogs. Thoracic duct lymph, mesenteric venous blood and arterial blood were examined before and during intestinal ischaemia and after revascularization of the small bowel. Venous blood was the major route of transport of lactic acid and lactate dehydrogenase from the ischaemic bowel. Endotoxin activity determined by the limulus test was found in the lymph before the induction of intestinal ischaemia in 4 of 6 dogs while it was absent in arterial blood. After one hour lasting revascularization endotoxin was present in the lymph of all dogs and in 3 and 4 dogs in arterial and mesenteric venous blood respectively. It was demonstrated that limulus-positive substances escape from the intestine both via the lymph and blood.