Response of isolated liver to endotoxin

The present investigation was carried out to study the vascular responses of the canine liver to endotoxin. Isolated denervated livers were continuously weighed and perfused via arterial and venous inflow vessels. Significant increases in hepatic artery and portal vein pressures, resistances, and organ weights were observed after endotoxin. Vascular responses were not blocked by phentolamine or duplicated by injections of suspected vasoactive agents. Responses to endotoxin and 48/80 were not blocked by phenoxybenzamine, although the vasoconstriction resulting from epinephrine and histamine administration was obliterated. The liver vascular response to endotoxin was duplicated by increasing hepatic vein pressure by partial outflow obstruction. Evidence points to the intrahepatic venous system as the primary site of endotoxin action with a subsequent myogenic response in the hepatic arterial segment.