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

Abstract

A 1H NMR technique was developed 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, the background signals were suppressed from lipids and H2O and the CH3 resonance of lactate was resolved at 1.33 ppm. The technique is highly selective and selects the CH3 resonance of Ala 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. This technique was applied to study the metabolic effect of ethanol in perfused mouse liver and the rate of formation of lactate from pyruvate is increased by a factor of 2.8 when ethanol is added.