Effect of endotoxin on capillary permeability to macromolecules

Abstract

The intravenous injection of Escherichia coli endotoxin (3 mg/kg) into dogs caused an increase in lymph flow from the thoracic duct. The lymph concentrations of macromolecules (dextran with mol. wt. of 250,000, albumin-I¹³¹, and endogenous proteins) increased and the lymph-to-plasma ratios approached 1. These results indicate that E. coli endotoxin causes an increase in capillary permeability to both the fluid and the macromolecules in plasma. The increase in capillary permeability for albumin-I¹³¹ was greater than that for dextran with mol. wt. of 250,000. Eighty minutes after endotoxin, the lymph flow returned to normal, but albumin-I¹³¹ and dextran injected at this time were still transferred into the thoracic duct lymph at enhanced rates.