Effect of fasting and acute ethanol administration on the energy state of in vivo liver as measured by 31P-NMR spectroscopy.
The effects of 48 h fasting, administration of ethanol or 2,4-dinitrophenol, on the phosphorus-containing metabolites in liver in vivo have been determined utilizing 31P nuclear magnetic resonance spectroscopy. These measurements were combined with determinations of metabolite concentrations in livers which were freeze-clamped immediately after the NMR measurements were completed. Administration of sub-lethal amounts of dinitrophenol dramatically decreased ATP and increased Pi concentrations in liver in vivo as indicated by a 2.7-fold increase in the NMR-derived [Pi]/[ATP] ratio. Ethanol administration to fed animals increased the NMR-derived [Pi]/[ATP] ratio 27%; in contrast, the same amount of ethanol administered to fasted animals decreased the NMR-derived [Pi]/[ATP] ratio 30%. The NMR visible Pi and ADP represent about 50% and 15% of the total Pi and ADP, respectively. The phosphorylation potentials calculated from the NMR visible Pi and ADP were an order of magnitude higher than those obtained from metabolite concentrations in freeze-clamped tissue. There was no apparent correlation between the phosphorylation potentials derived from either the NMR spectral analyses or from metabolite concentrations and the hepatic [NAD+]/[NADH] ratio. The chemical shift of Pi indicated that ethanol administration elicited a decrease in pH of 0.1 unit in liver in vivo. Hepatic free [Mg2+] was increased 21% in fasted animals, but was unaffected by ethanol administration.
D000090:Acetoacetates / Q000378:metabolism; D000227:Adenine Nucleotides / Q000378:metabolism*; D000818:Animals; D004140:Dinitrophenols / Q000494:pharmacology; D000431:Ethanol / Q000378:metabolism*; D005215:Fasting; D005615:Freezing; D006863:Hydrogen-Ion Concentration; D006885:Hydroxybutyrates / Q000378:metabolism; D007773:Lactates / Q000378:metabolism; D008099:Liver / Q000378:metabolism*; D009682:Magnetic Resonance Spectroscopy; D008930:Mitochondria, Liver / Q000378:metabolism; D010710:Phosphates / Q000378:metabolism*; D011773:Pyruvates / Q000378:metabolism; D051381:Rats
D000090:Acetoacetates; D000227:Adenine Nucleotides; D004140:Dinitrophenols; D006885:Hydroxybutyrates; D007773:Lactates; D010710:Phosphates; D011773:Pyruvates; D000431:Ethanol; C016635:acetoacetic acid