Table 5.
Mean (SD) plasma concentrations and calculated rates of brain uptake for LAT1 amino acid substrates.
| Amino acid | Control, N = 51 | MSUD baseline, N = 11 | Study formula, N = 36 |
|---|---|---|---|
| Plasma concentration (μM) | |||
| Leucine | 119 (38) | 282 (277)a | 152 (138)b |
| Isoleucine | 65 (25) | 334 (98)a | 245 (89)a,b |
| Valine | 207 (65) | 575 (146)a | 425 (169)a,b |
| Phenylalanine | 55 (18) | 61 (9) | 77 (26)a |
| Tryptophan | 50 (19) | 23 (8)a | 70 (30)a,b |
| Tyrosine | 63 (24) | 79 (35) | 112 (56)a,b |
| Histidine | 87 (29) | 83 (18) | 94 (22) |
| Glutamine | 527 (146) | 578 (75) | 592 (100) |
| Methionine | 31 (10) | 26 (6) | 67 (58)a,b |
| Threonine | 120 (44) | 147 (46) | 249 (87)a,b |
| Calculated brain uptake (nmol/min g) | |||
| Leucine | 12.4 (2.2) | 15.7 (11.9) | 9.7 (7.0)a |
| Isoleucine | 3.5 (0.9) | 12.1 (3.6)a | 8.9 (3.3)a,b |
| Valine | 2.5 (0.5) | 4.6 (1.3)a | 3.4 (1.4)a,b |
| Phenylalanine | 10.4 (1.9) | 8.2 (3.0)a | 9.3 (1.7)a |
| Tryptophan | 9.6 (3.0) | 3.1 (1.6)a | 8.5 (3.0)b |
| Tyrosine | 4.8 (1.3) | 4.3 (2.4) | 5.5 (2.0) |
| Histidine | 2.8 (0.9) | 1.8 (0.5)a | 1.9 (0.5)a |
| Glutamine | 1.4 (0.6) | 1.0 (0.3)a | 1.0 (0.3)a |
| Methionine | 1.0 (0.3) | 0.6 (0.2) | 1.3 (0.8)b |
| Threonine | 0.5 (0.1) | 0.4 (0.2) | 0.6 (0.2)a,b |
a
Different than control (Tukey p < 0.05).
b
Different than MSUD baseline (Tukey p < 0.05).