title: Endothelin-induced vasoconstriction in isolated perfused liver preparations from normal and cirrhotic rats.
abstract: Isolated, perfused rat liver preparations (IPRL), obtained from rats with carbon tetrachloride-induced cirrhosis and normal controls, were used to investigate responses to the vasoactive peptide endothelin-1 (ET-1). The mean perfusion resistance (R) of cirrhotic IPRL was significantly greater than that of controls (2.63 +/- 0.24 vs 1.54 +/- 0.14 mmHg/mL per min per g; P < 0.01). Both control and cirrhotic IPRL demonstrated a concentration-related increase in resistance (delta R) in response to ET-1, with a minimum effective concentration of approximately 3 x 10(-11) mol/L. The EC50 (-log of the 50% effective concentration) was not significantly different between cirrhotic and control IPRL (8.48 +/- 0.19 and 8.79 +/- 0.11, respectively); however, the maximum response to ET-1 was significantly greater in cirrhotic preparations (R: 10.4 +/- 2.2 vs 4.4 +/- 0.5 mmHg/mL per min per g, P < 0.01; DR, 7.8 +/- 2.1 vs 2.8 +/- 0.4 mmHg/mL per min per g, P < 0.01). Following maximal stimulation by ET-1, the mean portal-hepatic venous pressure gradient at a physiological flow rate of 1 mL/min per g was approximately 90% greater across cirrhotic IPRL than that across normal IPRL (11.2 +/- 2.0 vs 5.9 +/- 0.9 mmHg, respectively; P < 0.05). These results support the hypothesis that endogenously released ET-1 has a significant influence on the portal vascular resistance of cirrhotic liver in vivo and has an important role in the pathogenesis of portal hypertension.
authors.affiliation: Department of Pathology, University of Melbourne, Parkville, Victoria, Australia.
authors.forename: A J
authors.initials: AJ
authors.lastname: Elliot
authors.forename: L T
authors.initials: LT
authors.lastname: Vo
authors.forename: V L
authors.initials: VL
authors.lastname: Grossman
authors.forename: P S
authors.initials: PS
authors.lastname: Bhathal
authors.forename: H J
authors.initials: HJ
authors.lastname: Grossman
mesh_terms: D000818:Animals; D002252:Carbon Tetrachloride Poisoning / Q000503:physiopathology; D019332:Endothelin-1 / Q000494:pharmacology*; D006975:Hypertension, Portal / Q000209:etiology; D008099:Liver / Q000098:blood supply / Q000187:drug effects* / Q000473:pathology; D008102:Liver Circulation / Q000187:drug effects*; D008106:Liver Cirrhosis, Experimental / Q000139:chemically induced / Q000503:physiopathology*; D008297:Male; D010477:Perfusion; D017082:Portal Pressure / Q000187:drug effects; D011169:Portal Vein / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D014661:Vasoconstriction / Q000187:drug effects*
chemical_list: D019332:Endothelin-1