Cholestasis predisposes to hypersensitivity to LPS, leading to potential septic complications. We set out to characterize the involvement of Kupffer cell (KC) activation in the hepatic microcirculatory and structural consequences of obstructive jaundice in the presence and absence of acute endotoxemia. The hepatic microcirculatory consequences of 3-day extrahepatic bile duct ligation (BDL) were assessed in rats. The contributions of changes in hepatic perfusion, leukocyte influx, and proinflammatory cytokine release to the development of hepatic structural damage were also determined. Furthermore, the corresponding consequences of BDL in combination with acute (2-h) endotoxemia (1 mg kg(-1) LPS, i.v.) were compared with those observed after LPS alone. In a second series, the same protocols were applied in identical groups of rats where the KC function was inhibited with 24-h gadolinium chloride pretreatment (10 mg kg(-1), i.v.). Bile duct ligation induced minor inflammatory reactions but caused a marked reduction in hepatic sinusoidal perfusion and severe histological damage. LPS treatment, however, elicited an approximately 5-fold increase in leukocyte adherence in the central venules and pronounced IL-6 and TNF-alpha release, but without significant structural damage. The combination of BDL with LPS enhanced the perfusion failure, leukocyte sticking/deposition, and proinflammatory cytokine release; most of these changes can be effectively ameliorated by gadolinium chloride. In conclusion, when obstructive jaundice is followed by a second hit of LPS, perfusion failure, liver inflammation, and structural damage are enhanced, the KCs playing a decisive role in this scenario. Therapeutic strategies aimed at KC blockade can potentially reduce the risk of inflammatory complications in cholestasis.