title: Ethanol perfusion increases the yield of oxidative phosphorylation in isolated liver of fed rats.
abstract: The question arises as to the effect of ethanol on the actual yield of oxidative phosphorylation in the whole liver because of contradictory results reported in isolated hepatic mitochondria. The adenosine triphosphate (ATP) content of liver isolated from fed rats and perfused in the presence (10 mM) and absence of ethanol was continuously evaluated using 31P Nuclear Magnetic Resonance (NMR). An accurate estimation of mitochondrial ATP synthesis in the whole organ was obtained by subtracting the glycolytic ATP supply from the total ATP production. Simultaneously, the respiratory activity was assessed using O(2) Clark electrodes. The data indicate that ethanol enhanced the net consumption of ATP, leading to a new steady state of the ATP content. ATP synthesis was also found higher under ethanol [1.86+/-0.02 micromol/min g wet weight (min g ww)] than in control [1.44+/-0.18 micromol/min g ww]. However, mitochondrial respiration remained unchanged [2.20+/-0.13 micromol/min g ww] and, consequently, the in situ mitochondrial ATP/O ratio increased from 0.33+/-0.035 (control) to 0.42+/-0.015 (ethanol). The increase of the oxidative phosphorylation yield in the whole liver may be linked to the decrease in cytochrome oxidase activity induced by ethanol [FEBS Lett. 468 (2000) 239]. The significant raise (27%) of the ATP/O ratio was not sufficient to maintain the ATP level following ethanol-increased ATP consumption.
authors: Centre de Résonance Magnétique des Systèmes Biologiques, UMR 5536 CNRS-Université de Bordeaux 2, 146 rue Léo Saignat, F-33076 Bordeaux Cedex, France. mcdb@rmsb.u-bordeaux2.fr
authors: Marie-Christine
authors: MC
authors: Beauvieux
authors: Pierre
authors: P
authors: Tissier
authors: Patrice
authors: P
authors: Couzigou
authors: Henri
authors: H
authors: Gin
authors: Paul
authors: P
authors: Canioni
authors: Jean-Louis
authors: JL
authors: Gallis
mesh_terms: D000255:Adenosine Triphosphate / Q000032:analysis / Q000378:metabolism; D000818:Animals; D000431:Ethanol / Q000494:pharmacology*; D066298:In Vitro Techniques; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D008930:Mitochondria, Liver / Q000737:chemistry / Q000378:metabolism; D010085:Oxidative Phosphorylation / Q000187:drug effects; D010100:Oxygen / Q000032:analysis; D010101:Oxygen Consumption; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D013997:Time Factors
chemical_list: D000431:Ethanol; D000255:Adenosine Triphosphate; D010100:Oxygen