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Simultaneous in vivo monitoring of hepatic glucose and glucose‐6‐phosphate by 13 C‐NMR spectroscopy
Author(s) -
Künnecke Basil,
Küstermann Ekkehard,
Seelig Joachim
Publication year - 2000
Publication title -
magnetic resonance in medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.696
H-Index - 225
eISSN - 1522-2594
pISSN - 0740-3194
DOI - 10.1002/1522-2594(200010)44:4<556::aid-mrm9>3.0.co;2-3
Subject(s) - in vivo , glucose 6 phosphate , nuclear magnetic resonance spectroscopy , chemistry , substrate (aquarium) , spectroscopy , carbohydrate metabolism , biochemistry , nuclear magnetic resonance , enzyme , biology , stereochemistry , ecology , physics , microbiology and biotechnology , quantum mechanics
Hepatic glucose‐6‐phosphate (G6P) was monitored non‐invasively in rat liver by in vivo 13 C NMR spectroscopy after infusion of [1‐ 13 C] glucose. The phosphorylation of glucose to G6P yields small but characteristic displacements for all of its 13 C‐NMR resonances relative to those of glucose. It is demonstrated that in vivo 13 C‐NMR spectroscopy at 7 Tesla provides the spectral sensitivity and resolution to detect hepatic G6P present at sub‐millimolar concentration as partially resolved low‐field shoulders of the glucose C 1 resonances at 96.86 ppm ( C 1β) and 93.02 ppm ( C 1α). Upon 13 C‐labeling, the intracellular conversion of [1‐ 13 C] glucose to [1‐ 13 C] G6P could be monitored, which allowed the hepatic glucose‐G6P substrate cycle to be assessed in situ. The close correlation found for the 13 C labeling patterns of glucose and G6P supports the concept of an active substrate cycle whose rate exceeds that of net hepatic glucose metabolism. High‐resolution 13 C‐NMR spectroscopy and biochemical analyses of tissue biopsies collected at the end of the experiments confirmed qualitatively the findings obtained in vivo. Magn Reson Med 44:556–562, 2000. © 2000 Wiley‐Liss, Inc.