A 1H NMR technique for observing metabolite signals in the spectrum of perfused liver.

We have developed a 1H NMR technique to selectively edit the spectrum of perfused liver for specific resonances of metabolites that occur in low concentration. The method employs selective DANTE pulses, which avoid exciting the water signal and at the same time control the J modulation effect in the homonuclear spin-echo experiment. By difference spectroscopy, we have suppressed the background signals from lipids and water and have resolved the CH3 resonance of lactate at 1.33 ppm. Moreover, the technique is highly selective and allows us to select the CH3 resonance of alanine at 1.47 ppm in the presence of the CH3 resonance of lactate at 1.33 ppm, even though the latter was much larger before editing. We have applied this technique to study the metabolic effect of ethanol in perfused mouse liver and have observed that the rate of formation of lactate from pyruvate is increased by a factor of 2.8 when ethanol is added.