Figure 2. Time course for ¹³C-glucose infusions in HOT-bearing mice.

(A) Four mice bearing HOTs derived from the same parental tumor were infused with [U-¹³C]glucose for the indicated times. The time course shows ¹³C enrichment (in %) of plasma glucose in the individual mice used in this time course experiment. Enrichment at time 0 was assumed to be 0%. All mice received a bolus of [U-¹³C]glucose over 1 minute followed by a continuous [U-¹³C]glucose infusion as described in Experimental Procedures.

(B) NMR isotopomer analysis for carbons 2, 3 and 4 of glutamate and glutamine. None of these carbons demonstrated any appreciable change in ¹³C labeling after 150 minutes of [U-¹³C]glucose infusion.