Release of endothelin-1 in strangulation obstruction of the small bowel in pigs.
Evidence has been provided that increased portal vein pressure results in increased release of endothelin-1 (ET-1). Strangulation obstruction is associated with increased venous pressure, and we wanted to determine if it is associated with increased local release of ET-1 and elevated concentration of ET-1 in systemic blood. Strangulation obstruction was induced by elevating pressure in a gasket placed around a loop of ileum until venous pressure reached 50 mm Hg. Ischemia in a bowel loop was induced by arterial clamping, reducing blood flow by 70%. Blood samples were collected before and after 30, 90, and 180 min of strangulation or ischemia. ET-1 was determined by radioimmunoassay following acidification and extraction on C18 columns. In strangulated loop the blood flow decreased by 70%. ET-1 concentration remained around 5 pg/ml in arterial blood, increased fourfold in strangulated venous blood, and remained unchanged in venous blood from control bowel. The release of ET-1 from the strangulated loop to blood increased twofold. Ischemia resulted in reduced release of ET-1. It is concluded that strangulation obstruction causes increased release of ET-1 to venous blood in the strangulated loop, but not increased ET-1 concentration in systemic blood. The increased ET-1 release was probably due to increased venous pressure, not to low blood flow.
Fevang
J
J
Institute of Surgery, University of Bergen, Bergen, N-5021, Norway.
Ovrebo
K
K
Ostgaard
G
G
Aakvaag
A
A
Svanes
K
K
D000818:Animals; D019332:Endothelin-1 / Q000378:metabolism*; D006339:Heart Rate; D007415:Intestinal Obstruction / Q000378:metabolism*; D007422:Intestines / Q000098:blood supply; D007511:Ischemia / Q000378:metabolism; D012039:Regional Blood Flow; D013552:Swine; D014690:Venous Pressure
D019332:Endothelin-1