Metabolites include GABA (2A; γ-aminobutyric acid), GHB (2B; γ-hydroxybutyric acid), SSA (2C; succinic semialdehyde), DHHA (2D; 4,5-dihydroxyhexanoic acid) and D-2-HG (2E; D-2-hydroxyglutaric acid). Tissues surveyed included liver (L), kidney (K) and brain (B). Data depicted as mean ± SEM, with error bars indicating SEM and central horizontal bar indicating mean. Student’s t test was used for statistical evaluation (two-tailed).