A method for measuring cerebral glucose metabolism in vivo by 13C-NMR spectroscopy

Current methods for estimating the rate of cerebral glucose utilization (CMRglc) typically measure metabolic activity for 40 min or longer subsequent to administration of [C-13]glucose, 2-[C-14]deoxyglucose, or 2-[F-18]deoxyglucose. We report preliminary findings on estimating CMRglc for a period of 15 min by use of 2-[6-C-13]deoxyglucose. After a 24-hr fast, rats were anesthetized, infused with [1-C-13]glucose for 50 min, and injected with 2-[6-C-13]deoxyglucose (500 mg/kg). During the subsequent 12.95 min the estimated value of CMRglc was 0.6 +/- 0.4 micromol/min/g (mean +/- SD, N = 7), in agreement with values reported for anesthetized rats studied with the 2-[C-14]deoxyglucose method and other C-13-NMR methods that measure CMRglc. In rats injected with bicuculline methiodide (a known stimulant of CMRglc), CMRglc increased by more than 75% during 12.95 min following injection of bicuculline (Wilcoxon signed rank test, P = 0.042, N = 8).