(A) Illustration of [U-13C]glutamine metabolism. See legend to Fig. 3A and Supplemental Experimental Procedures for details and abbreviations.
(B) Brain and (C) tumor spectra from a mouse with an M-2 HOT infused with [U-13C]glutamine. Insets are glutamate (GLU) and glutamine (GLN) C3 and C4.
(D) Expansion of GLU4 and LAC3 multiplets in three tumors infused with [U-13C]-glutamine. Arrows highlight the 2–3 doublet in lactate and the 4–5 doublet in glutamate.
(E) 13C enrichment in plasma glutamine, glucose and lactate of mice infused with [U-13C]glutamine. Data are the average ± S.D. of three HOT-bearing mice.
(F) Schematic of metabolic activities occurring outside of the tumor by which [U-13C]-glutamine is converted to glucose and lactate (dashed green arrows), which are detected in the plasma. Subsequent metabolism in the tumor (black arrows) uses 13C glucose and/or lactate to supply the CAC.