Acute lung injury (ALI) is a common complication of different conditions like sepsis, shock and trauma, which may emerge into full-blown acute respiratory distress syndrome (ARDS). During the last 15 years, participation of the endothelin-1 (ET-1) system in the pathogenesis of ALI/ARDS has been intensively studied. In sepsis-induced acute lung injury (ALI), endothelin-1 (ET-1) is suspected of increasing lung capillary pressure and probably permeability. In present study, we studied pulmonary hemodynamic, volumetric and permeability effects of the non-selective ET-1 receptor antagonist, tezosentan, in animals with endotoxin or sepsis-induced ALI. We also studied the activation of protein kinase C alpha and expression of mRNA for prepro-ET-1 and its receptors in animals lung tissue cells. Additionally, we investigated the relationship between the plasma concentration of ET-1 and extravascular lung water index (EVLWI) in septicemic patients.