Figure 3. Male transformed astrocytes exhibit higher glutamine utilization.

A, Schematic of major downstream metabolic pathways of glutamine. B-F, Label incorporation of [¹³C₅¹⁵N₂]glutamine ([¹³C₅¹⁵N₂]Gln) in transformed astrocytes. Label incorporation into nucleotides (B) and lipids (F) was measured via solid-state NMR. 50.3-MHz ¹⁵N NMR spectra (B) and 125.7-MHz cross-polarization magic-angle spinning ¹³C NMR spectra (F) are shown. Label incorporation into reduced (GSH) and oxidized (GSSG) glutathione (C) was measured via LC/MS. Prominent (fully labeled) isotopologues for GSH (m+5) and GSSG (m+10) are shown. Label incorporation into amino acids (D) and TCA cycle intermediates (E) was measured via GC/MS. Prominent isotopologues for glutamate (m+6), aspartate (m+5), and all other amino acids (m+1) are shown. Prominent labels (one turn of the TCA cycle) for α-KG (m+5), citrate (oxidative TCA cycle (m+4); reductive TCA cycle (m+5)), succinate (m+4), fumarate (m+4), and malate (m+4) are shown. Data are mean +/− SEM of n=3/sex (three independent experiments, one male and female cell line). ***p<0.001; linear mixed effects model (C). *q<0.05, **q<0.01, ****q<0.0001; linear mixed effects model, FDR adjusted p-values (D-E). See also Tables S3 and S4.