[The recovery of energy metabolism from hypothermic preservation in the rat liver].
Functional recovery of the preserved organ depends on the recovery of energy metabolism. To assess this recovery, adenosine triphosphate (ATP) level and tissue pH were measured by phosphorus nuclear magnetic resonance. Oxygen consumption, bile flow rate and glucose output were also measured before and after preservation. During preservation with Euro-Collins solution at 0 degrees C, ATP signal decreased to noise-level. After preservation, liver was reperfused with modified Krebs-Henseleit solution at 37 degrees C. ATP level of the 6 and 24h preserved liver recovered to 92%, and 76% of the pre-preservation level, respectively. Tissue pH recovered to the pre-preservation level after both 6 and 24h preservation. However, oxygen consumption of the 24h preserved liver was higher than that of the fresh liver. These findings support the idea that the efficiency of oxidative phosphorylation decreases after 24h preservation, but still remains the possibility of increase in ATP hydrolysis by other processes than bile secretion. In another experiment, gluconeogenesis was activated with norepinephrine (NE), and changes in energy metabolism were examined. Glucose output was less increased by NE stimulation in the 24h preserved liver than in the fresh liver. By NE administration, ATP level decreased 5-10% in the fresh liver, and 20-25% in the 24h preserved liver. In the 24h preserved liver, the increment in oxygen consumption induced by NE administration was less than a half of the fresh liver. These results suggest that a supply of ATP is short when an energy demand is increased in the 24h preserved liver, and that this shortage of ATP supply is mainly due to the deterioration of mitochondrial respiration.
Tsukamoto
K
K
Second Department of Surgery, Kyoto Prefectural University of Medicine, Japan.
D000818:Animals; D003080:Cold Temperature; D004734:Energy Metabolism; D005943:Gluconeogenesis; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008930:Mitochondria, Liver / Q000378:metabolism; D009926:Organ Preservation; D051381:Rats; D011919:Rats, Inbred Strains