title: Carbohydrate metabolism of the rat C6 glioma. An in vivo 13C and in vitro 1H magnetic resonance spectroscopy study.
abstract: Surface coil 13C nuclear magnetic resonance (NMR) spectroscopy was used to investigate the in vivo carbohydrate metabolism of rat C6 gliomas during and after infusion with [1-13C] glucose. In vivo 1H-decoupled 13C NMR spectra of the glioma following infusion with [1-13C]glucose revealed the direct production of [3-13C]lactic acid, [1-13C]glycogen, and [4-13C], [3-13C], and [2-13C]glutamate/glutamine. Lactate levels of in vivo gliomas increased and reached steady state levels during [1-13C]glucose infusion, and decreased following termination of infusion. Complementary in vitro studies using supernatant media collected from C6 glioma cells incubated with media containing [1-13C] or [6-13C]glucose and glutamine were examined by 1H NMR spectroscopy. The [3-(13C/12C)]lactate ratios obtained from 1H spectra of supernatant media containing [1-13C]glucose revealed the percentage of glucose metabolized through the hexose monophosphate shunt to be 10.01 +/- 0.85% (n = 3), while similar measurements of media containing [6-13C]glucose and glutamine showed that glutaminolysis contributed 9.0 +/- 1.0% of total lactate production under these conditions. Enzymatic analysis of media determined lactate production to be 139 +/- 9 nmol per 10(6) cells per h (n = 4). These measurements demonstrate the ability of NMR to monitor brain tumor carbohydrate metabolism both in vitro and in vivo.
authors.affiliation: Department of Biophysics, University of California, Davis 95616.
authors.forename: B D
authors.initials: BD
authors.lastname: Ross
authors.forename: R J
authors.initials: RJ
authors.lastname: Higgins
authors.forename: J E
authors.initials: JE
authors.lastname: Boggan
authors.forename: J A
authors.initials: JA
authors.lastname: Willis
authors.forename: B
authors.initials: B
authors.lastname: Knittel
authors.forename: S W
authors.initials: SW
authors.lastname: Unger
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D001932:Brain Neoplasms / Q000175:diagnosis* / Q000378:metabolism; D050260:Carbohydrate Metabolism; D005260:Female; D005910:Glioma / Q000175:diagnosis* / Q000378:metabolism; D066298:In Vitro Techniques; D009682:Magnetic Resonance Spectroscopy; D051381:Rats; D011916:Rats, Inbred F344