Fig. 1.

Time course of ¹³C labeling in mouse hearts following [U-¹³C]glucose infusion. Mice were infused with [U-¹³C]glucose for different durations as indicated followed by NMR analysis of heart tissue. Time courses show ¹³C enrichment of glucose at the C-1 position (A), lactate at the C-3 position (B), and alanine at the C-3 position (C). Enrichment at time 0 is assumed to be 0%. The blue bar estimates the time of maximal ¹³C enrichment. Data are shown as means ± SD with n = 3 mice/analyzed time point or n = 2 where no SD bars are shown.