Endotoxin: routes of transport in experimental peritonitis

A quantitative endotoxin assay was applied in this study of endotoxin transport from the infected abdomen. In rats with fecal peritonitis, extremely high concentrations were found in thoracic duct lymph (approximately 400 times higher than those found in arterial and portal vein plasma). Taking flow rates into account, the thoracic duct carries 34 ng/hour and the protal vein 49 ng/hour after 2 hours of peritonitis. Endotoxin quantities transported by the portal vein never exceed the proposed endotoxin filtrating capacity of the liver. Furthermore, the onset of systemic endotoxemia parallels the appearance of endotoxin in the thoracic duct. The hypothesis put forward is that the development of systemic endotoxemia is mainly mediated by lymphatic transport. The results also indicate that endotoxin is normally absorbed from the intestine and transported by portal blood.