The effect of anesthesia on the epimerization of 2-deoxy-2-fluoro-D-glucose(-6-phosphate) to 2-deoxy-2-fluoro-D-mannose(-6-phosphate) in mice was demonstrated with 19F NMR spectroscopy of excised tissue specimens from heart, muscle, and brain. Spectra from each of six excised organs confirmed that pretreatment with an anesthetic suppressed the conversion ratio, FDM/(FDG + FDM), in brain at 3 h from 52 +/- 5 to 30 +/- 6% under the dose of 100 mg/kg. We propose potential applications for NMR monitoring of FDG-FDM conversion, including the assessment of regional brain metabolism and the evaluation of various pharmacologic agents.