Table 4. Urinary excretion and kinetic parameters for 13C-uracil and its metabolites.
Substance | Parameter | 50 mg | 100 mg | 200 mg |
---|---|---|---|---|
13C-uracil | Ae (mg) | 0.35 ± 0.19 | 1.21 ± 0.80 | 4.52 ± 2.80 |
CLR (l h−1) | 6.8 ± 1.6 | 7.2 ± 2.1 | 7.7 ± 1.4 | |
Excretion (%/dose) | 0.7 ± 0.4 | 1.2 ± 0.8 | 2.3 ± 1.4 | |
13C-DHU | Ae (mg) | 0.10 ± 0.05 | 0.28 ± 0.14 | 0.83 ± 0.44 |
CLR (l h−1) | 0.7 ± 0.2 | 0.7 ± 0.2 | 0.8 ± 0.3 | |
Excretion (%/dose) | 0.2 ± 0.1 | 0.3 ± 0.1 | 0.4 ± 0.2 | |
13C-UPA | Ae (mg) | 0.21 ± 0.10 | 0.53 ± 0.31 | 1.33 ± 0.91 |
CLR (l h−1) | 17.1 ± 8.7 | 13.4 ± 6.3 | 9.1 ± 4.1 | |
Excretion (%/dose) | 0.4 ± 0.2 | 0.5 ± 0.3 | 0.6 ± 0.4 |
13C-DHU: 5,6-dihydrouracil (2-13C)]13C-UPA,β-ureidopropionic acid (ureido-13C). Values: mean ± SD (n = 12).