Changes in prostaglandin and nitric oxide levels in the hyperdynamic circulation following liver resection

Background and Aims: Significant changes in hepatic haemodynamics occur aft er major hepatectomy, but the pathogenesis of this phenomenon is unclear. T his study investigates the serum profile of prostaglandin and nitric oxide in the hepatic and systemic circulation before and after hepatectomy and th e temporal relationship of these to changes in the hepatic blood flow. Methods: Blood samples were collected from the internal jugular, portal and hepatic veins of six Yorkshire pigs (17-25 kg) before, immediately after a nd 48 h after partial hepatectomy. Results: Serum levels of prostacyclin I-2 (PGI(2)) and prostaglandin E-2 (P GE(2)) from the systemic circulation, the portal circulation and from the h epatic veins were found to differ considerably even before hepatectomy. Aft er the hepatectomy was performed, there was a significant rise in PGI(2) le vels in the systemic circulation (P = 0.027). Hepatic blood flow and cardia c output were measured before hepatectomy, 24 and 48h after hepatectomy in another six pigs. A significant increase in hepatic blood flow (P = 0.029) occurred after the hepatectomy and this was accompanied by a concomitant in crease in the cardiac output (P = 0.042). The increase in PGI(2) concentrat ion in the systemic circulation after hepatectomy appears to accompany the development of hyperdynamic hepatic and systemic circulations. No significa nt change was found in circulating PGE(2) levels in the systemic, portal an d hepatic veins at the three collection intervals (i.e. pre, post and 48 h after hepatectomy). The PGE(2) levels in the hepatic vein, however, were si gnificantly higher from than in the portal vein (P = 0.028). No significant changes were observed in the level of nitric oxide. Conclusion: This study demonstrates an increase in the total hepatic blood flow after hepatectomy together with a threefold increase in prostacyclin i n the systemic circulation. The liver was identified as the main source of circulatory prostaglandin. (C) 2000 Blackwell Science Asia Pty Ltd.