Fig. 7

TCA cycle intermediates are reduced but glutamine entry into the TCA cycle is intact in Gpt2-null synaptosomes. A Baseline malate and fumarate levels are reduced in Gpt2-null synaptosomes. Each dot represents a different sample from wild-type (black) or Gpt2-null (red) mice at P18. Baseline wild-type vs. Gpt2-null malate: *P = 0.03; fumarate: *P = 0.03. B Malate levels are rescued by alpha-ketoglutarate in Gpt2-null synaptosomes. Each dot represents a different sample from wild-type (black) or Gpt2-null (red) mice at P18. Malate wild-type vs. Gpt2-null no supplement: **P = 0.003; wild-type no supplement vs. + alpha-ketoglutarate: **P = 0.002; Gpt2-null no supplement vs. + alpha-ketoglutarate: **P = 0.002; Wild-type no supplement vs. Gpt2-null + alpha-ketoglutarate: P = 0.84. A two-way ANOVA was performed with Tukey’s multiple comparison correction and the reported p-values are adjusted p-values. C Fractional enrichments of carbon labeled TCA cycle intermediates using the uniformly carbon labeled [U-¹³C]-Glutamine precursor is unchanged in Gpt2-null synaptosomes. The metabolic pathways that label the carbons of TCA cycle intermediates are shown on the left. Fractional enrichments of m + 4 (4 heavy carbons) as a percentage are given on the right. Each dot represents synaptosome samples obtained from different wild-type (black) or Gpt2-null (red) mice at P18. Wild-type vs. Gpt2-null malate: P = 0.83; fumarate: P = 0.88. A two-way ANOVA was performed with Tukey’s multiple comparison correction and the reported p-values are adjusted p-values. D ATP levels are unchanged in Gpt2-null synaptosomes. Each dot represents synaptosome samples obtained from different wild-type (black) or Gpt2-null (red) mice at P18. ATP levels were enzymatically determined. Wild-type vs. Gpt2-null: P = 0.35. E ATP levels as determined by LC-MS. Each dot represents synaptosome samples obtained from different wild-type (black) or Gpt2-null (red) mice at P18. ATP levels were enzymatically determined. Wild-type vs. Gpt2-null: P = 0.12. F NAD to NADH ratio is unchanged in Gpt2-null synaptosomes. Each dot represents normalized peak intensities of synaptosome samples obtained from different wild-type (black) or Gpt2-null (red) mice at P18 as determined by LC-MS. Wild-type vs. Gpt2-null: P = 0.31. G NADP to NADPH ratio is unchanged in Gpt2-null synaptosomes. Each dot represents normalized peak intensities of synaptosome samples obtained from different wild-type (black) or Gpt2-null (red) mice at P18 as determined by LC-MS. Wild-type vs. Gpt2-null: P = 0.23