[Study of the ischemic effect on the hepatic energy metabolism]

The changes of hepatic energy metabolism during normothermic and hypothermic ischemia were investigated using rats with portajugular shunt. In addition, some blood parameters were estimated as to whether they could reflect the changes in hepatic energy level (represented by energy charge, EC). In this study, [pyruvate]/[lactate] x 1/K(K = 1.11 x 10(-4)) and [2-oxoglutarate] x [ammonia]/[glutamate] x 1/K(K = 3.87 x 10(-3) mmole) were used as indexes of cytosolic and mitochondrial redox state, respectively. The following results were obtained. 1) Though hepatic EC recovered after 30 minutes of ischemia, it didn't recover after 60 minutes of normothermic ischemia. 2) The recovery of the hepatic EC even after 60 minutes of ischemia was observed in hypothermic condition. 3) Mitochondrial redox state changed like hepatic EC, however, some dissociations were observed between cytosolic redox state and hepatic EC in hypothermic ischemia. 4) The changes of mitochondrial and cytosolic redox state were reflected in those of arterial ammonia and lactate level, respectively. As a result, hypothermia can prolong the safe ischemic period due to its stabilizing effect on mitochondrial redox state. In addition, the changes of the hepatic EC are reflected in those of arterial ammonia and lactate level. In hypothermic condition, however, ammonia seemed a better parameter than lactate in assessing hepatic EC.