The effects of organ preservation on mitochondrial oxidative phosphorylation activity, adenylate hepatic energy charge, cytochrome content, and redox state of NAD+/NADH couple in rat liver transplantation were compared between a nonpreservation group and a preservation group with grafts preserved for 12 hr in Euro-Collin's solution. At 3 hr after transplantation, the energy charge in the preservation group decreased to 0.60 +/- 0.02 from the control value of 0.86 +/- 0.01, accompanied by a reduction of intramitochondrial redox state of NAD+/NADH couple. In contrast, in the nonpreservation group, the decrease in energy charge was minimally decreased to 0.79 +/- 0.04 due to the compensatory enhancement of mitochondrial oxidative phosphorylation activity. These results suggest that an enhanced mitochondrial ATP synthesis and a reduced intramitochondrial redox state are important factors affecting survival following rat liver transplantation.