Noninvasive demonstration of in vivo 3-fluoro-3-deoxy-D-glucose metabolism in rat brain by 19F nuclear magnetic resonance spectroscopy: suitable probe for monitoring cerebral aldose reductase activities.

The metabolism of 3-fluoro-3-deoxy-D-glucose (3-FDG) in rat brain in vivo was investigated noninvasively using 19F nuclear magnetic resonance (NMR) spectroscopy. Following an intravenous infusion of 3-FDG, 400 mg/kg, four resonances assigned to the alpha and beta anomers of 3-FDG, 3-fluoro-3-deoxy-D-sorbitol, and 3-fluoro-3-deoxy-D-fructose were clearly resolved in brain, a result indicating that 3-FDG is metabolized primarily into the aldose reductase sorbitol (ARS) pathway. An orally administered aldose reductase inhibitor, sorbinil, caused reduction of the flux of 3-FDG into the ARS, an observation suggesting that the method can be applied in quantitative studies of ARS pathway activities. Studies of 24-h urine specimens showed that in addition to the two metabolites observed in brain, F- was excreted into the urine. 3-FDG appears to be a suitable metabolic probe for assessing glucose metabolism in the ARS pathway by in vivo 19F NMR spectroscopy.