Table 2.
Relative changes at 2 weeks of 24 h urine metabolites in control, MSG and NaHCO3 rats (n = 10 per group) using the 1H-NMR profiles.
| Metabolites | Chemical Shift (Multiplicity) | MSG and NaHCO3 Induced Metabolic Changes Compared to Control | The Acid Dissociation Constant (pKa) | |
|---|---|---|---|---|
| (−) Control vs. (+) MSG R2X = 44%, Q2Y = 0.75, p = 0.001 | (−) Control vs. (+) NaHCO3 R2X = 47%, Q2Y = 0.95, p = 0.001 |
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| 3-carboxy-2-methyl-3-oxopropanamine | 1.08 (d); 2.49 (m); 3.19(m); 3.56 (m); 3.72 (m) | - | (*0.95)(∆3.33 × 10−10) | |
| Beta-hydroxyisovalerate | 1.28 (s) | (*0.77)(∆6.19 × 10−5) | (*0.89)(∆1.83 × 10−7) | pKa1 = 4.55 |
| 5-aminovalerate | 1.68 (m); 2.21 (t); 3.02 (t) | (*0.79)(∆3.35 × 10−5) | (*0.95)(∆1.38 × 10−10) | pKa1 = 4.27, pKa2 = 10.77 |
| 5-hydroxymethyl-4-methyluracil | 1.98 (s); 4.42 (s) | (*0.83)(∆5.84 × 10−6) | (*−0.84)(∆4.15 × 10−6) | pKa1 = 9.87 |
| Glutamate | 2.02 (m); 2.34 (m); 3.76 (m) | (*0.85)(∆2.31 × 10−6) | (*0.88)(∆2.91 × 10−7) | pKa1 = 2.19, pKa2 = 4.25, pKa3 = 9.67 |
| Succinate | 2.41 (s) | - | (*0.87)(∆8.10 × 10−7) | pKa1 = 4.16, pKa2 = 5.61 |
| Alpha-ketoglutarate | 2.44 (t); 3.01 (t) | (*0.75)(∆1.37 × 10−4) | (*0.89)(∆1.46 × 10−7) | pKa1 = 2.47, pKa2 = 4.68 |
| Citrate | 2.54 (d); 2.66 (d) | (*0.87)(∆5.10 × 10−7) | (*0.96)(∆4.63 × 10−11) | pKa1 = 3.14, pKa2 = 4.77, pKa3 = 6.39 |
| Methylamine | 2.61 (s) | (*0.52) (∆0.019) | - | pKa1 = 10.63 |
| Dimethylamine | 2.77 (s) | (*0.71)(∆4.76 × 10−4) | - | pKa1 = 2.36, pKa2 = 10.21 |
| Malonate | 3.11 (s) | (*0.74)(∆2.17 × 10−4) | (*0.97)(∆1.66 × 10−12) | pKa1 = 2.85, pKa2 = 5.70 |
| Choline | 3.21 (s); 3.52 (m); 4.07 (m) | - | (*0.80)(∆2.70 × 10−5) | pKa1 = 13.9 |
| Taurine | 3.25 (t); 3.43 (t) | (*−0.73)(∆2.69 × 10−4) | (*−0.80)(∆2.80 × 10−5) | pKa1 = 1.15, pKa2 = 9.06 |
R2X and Q2Y show the variance explained and predicted by each model while P values for all models were derived from the permutation test (n = 1000). (+) indicates a higher correlation, whereas (−) indicates a lower correlation of urinary metabolite after MSG and NaHCO3 consumption. (*) represents the correlation value and (∆) represents the p value of the specific peak. The bolded chemical shift per metabolite was used as the STOCSY driver peak and for deriving the correlation and p-value. (* p < 0.05, ** p < 0.01, *** p < 0.001). Abbreviations: s, singlet; d, doublet; t, triplet; m, multiplet, pKa; acid dissociation constant. Note; (−) Control vs. (+) NaCl, R2X = 38%, Q2Y = 0.12, p = 0.433.