ENDOTHELIN-1 LEVELS IN PORTAL VENOUS-BLOOD IN RELATION TO HEPATIC TISSUE MICROCIRCULATION DISTURBANCE AND HEPATIC CELL INJURY AFTER ISCHEMIA REPERFUSION/

This study was conducted to clarify the role of endothelin-1 in the po rtal vein after hepatic ischemia/reperfusion and to ascertain whether it is related to hepatic microcirculation disturbance. Using a canine ischemic liver model, the portal and systemic endothelin-1 levels were measured before ischemia, then after 1h and 2h of reperfusion, and co mparatively evaluated with the serum levels of GOT and lactic dehydrog enase (LDH). As an indicator of liver tissue microcirculation, tissue blood flow volume (TBF) was also measured in the site subjected to isc hemia. The animals were divided into: group 1, which received ischemia for 30 min; group 2, which received ischemia for 60 min; and group 3, which received a sequence repeated four times of 15-min ischemia and 10-min reperfusion. The portal endothelin-1 level became significantly elevated after reperfusion compared to that before ischemia in all gr oups, being significantly higher in group 2 than in the other groups. The systemic endothelin-1 level also increased after reperfusion; sign ificantly in group 2. The portal endothelin-1 level was generally high er than the systemic level, which again was statistically significant in group 2. After 2h of reperfusion, a significant positive correlatio n was found between the portal endothelin-1 level and serum LDH, where as a significant negative correlation was found between the portal end othelin-1 level and TBF. The finding that the portal endothelin-1 leve l became elevated after hepatic ischemia/reperfusion suggests that it probably plays an essential role in hepatic ischemia/reperfusion injur y by adversely influencing tissue microcirculation.