METABOLITES IN BRAIN AND THE RELATIONSHIP TO 2-DEOXYGLUCOSE METHOD

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The purity of radioactive glucose isolated as glucose-borate complex from anion exchange column chromatography was examined in this report. The elute of the Dowex AG 1 x 8 borate column was found to be contaminated with implicity which can be removed by cation exchange chromatography. This cationic metabolite was also found to comigrate with glucose on paper chromatography. The following structural and metabolic properties were also assessed to these unidentified metabolites: that they must carry polyhydroxy group and that they are formed from glucose-6-phosphate. The time-course of the production of the anionic and cationic metabolites seem to level off at about 7 min after the injection of labeled glucose to brain through the internal carotid artery, with the radioactivity in cationic fraction at about 1/3 of that in the anionic faction. Since metabolites of glucose in glycolysis and Krebs cycle carry negative charges, the production of the cationic metabolites may represent pathways of glucose metabolism not involved ine energy production. Our results indicated that the dephosphorylation of glucose-6-phosphate may not be as large as reported previously by us. Our results also indicate that about 30% of the flux through hexokinase may be channeled through pathways not involved in energy production.