Observation of glucose metabolism in the rat liver by in vivo 13C MR spectroscopy without proton decoupling.

Glucose metabolism in rat liver was investigated by in vivo 13C-MR spectroscopy using [1-13C]glucose. Experiments were performed with a 7.05 Tesla small bore MR system using a 13C surface coil without 1H decoupling. Sprague-Dawley rat was anesthetized and kept in the spine position. [1-13C]glucose (99% enriched) was injected intravenously in a dose of 1 g per kg of body weight. The circular surface coil of 25.4 mm in diameter was placed on the surgically exposed liver in the incised abdomen. A total time of one scan was about 8 min and time course for glycogenesis was observed every 10 min, for total 90 min. The in vivo 13C-1 carbon resonances of hepatic glucose and glycogen were well resolved in spite of splitting by J-coupling, enabling the time course for the relative change in concentrations for both metabolites to be established simultaneously. The 13C resonance of glucose gradually decreased, and the 13C resonance of glycogen gradually increased to peak level at 40 min after the injection of [1-13C]glucose. We have developed a simple method of 13C-MR spectroscopy for use in rat liver.