Measurement of 13C turnover into glutamate and glutamine pools in brain tumor patients

Malignant brain tumors are known to utilize acetate as an alternate carbon source in the citric acid cycle for their bioenergetics. 13C NMR based isotopomer analysis has been used to measure turnover of 13C-acetate carbons into glutamate and glutamine pools in tumors. Plasma from the patients infused with [1,2-13C]acetate further revealed the presence of 13C isotopomers of glutamine, glucose and lactate in the circulation that were generated due to metabolism of [1,2-13C]acetate by peripheral organs. In the tumor cells, [4-13C] and [3,4-13C] glutamate and glutamine isotopomers were generated from blood-borne 13C labeled glucose and lactate which were formed due to [1,2-13C[acetate metabolism of peripheral tissues. [4,5-13C] and [3,4,5-13C] glutamate and glutamine isotopomers were produced from [1,2-13C]acetyl-CoA that were derived from direct oxidation of [1,2-13C]acetate in the tumor This article is protected by copyright. All rights reserved.