The effect of PGE 2 on hepatic blood flow and bile indocyanin green in the rat

Abstract

The effect of Prostaglandin E2 (PGE2) on hepatic blood flow and bile excretion has been only partially investigated. We studied in the rat the effect of PGE2 on indocyanine green (ICG) clearance, bile flow and ICG recovery in the bile. PGE2 administered to rats at a rate of 2 μg/kg/min had no effect on ICG clearance as compared to vehicle-treated rats (14.6±0.15 Vs. 16.9±2.5 ml/mim/kg) and on bile flow(1.23±0.15 Vs. 1.24±0.11 μl/min/gm liver). However, ICG excretion in bile was significantly increased as compared to a vehicle-treated group, 0.48±0.09 and 0.25±0.02 μg/ μl bile, respectively (P<0.005). This effect of PGE2 on ICG recovery in bile was found to be dose-dependent, and when PGE2 was administered at a rate of 1μg/kg/min, bile ICG decreased to 0.33±0.10 μg/ μl bile. The effect of PGE2 on bile ICG is not due to an increased extraction of ICG by the liver since using the isolated perfused rat liver, the mean ICG extraction rate over a 20 minute period, with and without PGE2 infusion, was very similar, 33±3.5 and 37±6.2 percent, respectively. The lack of effect of PGE2 on ICG clearance and extraction on bile flow, with an increase in biliary excretion of ICG, suggests a decreased hepatic storage of ICG induced by PGE2 possibley due to an accelerated rate of ICG excretion from the hepatocytes to the bile canaliculi.