Molecular Distribution of Radiolabel in Tumors 2 Hours After Intravenous Injection of FU
| Injected radiotracer | Pretreatment with EU | n | % activity recovery during HPLC | % recovered activity | ||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| F− | FBAL + FUPA + FUH2 | FU | FUrd ± FdUrd | FUMP ± FdUMP | FUDP ± FdUDP | FUTP ± FdUTP | AIF | Unidentified peaks | ||||
| [18F]FU | No | 3 | 63 ± 3 | 5 ± 5 | 41 ± 5 | 3 ± 2 | 9 ± 7 | 10 ± 4 | 9 ± 1 | 11 ± 4 | 6 ± 2 | 6 ± 3 |
| [3H]FU | No | 2 | 81* | — | 72 ± 11† | 1 ± 0 | 1 ± 0 | 17 ± 14 | 1 ± 0 | 3 ± 0 | 5 ± 1 | 1 ± 1 |
| [18F]FU | Yes | 6 | 84 ± 4‡ | ND | 1 ± 0 | 46 ± 4 | 5 ± 1 | 12 ± 2 | 10 ± 1 | 11 ± 3 | 14 ± 1 | 1 ± 1 |
| [3H]FU | Yes | 2 | 81 ± 2 | — | 4 ± 0† | 24 ± 5 | 4 ± 1 | 12 ± 2 | 14 ± 4 | 22 ± 6 | 17 ± 5 | 4 ± 1 |
↵* Measurable for only 1 of 2 experiments.
↵† Data may include contribution from β-alanine.
↵‡ P < 0.01 relative to unmodulated [18F]FU.
Data are presented as mean ± SEM. EU = eniluracil; F− = fluoride ion; FBAL = α-fluoro-β-alanine; FUPA = α-fluoro-β-ureido-propanoic acid; FUH2 = dihydrofluorouracil; FUrd = fluorouridine; FdUrd = fluorodeoxyuridine; FUMP, FUDP, and FUTP, fluorouridine mono-, di-, and triphosphate, respectively; FdUMP, FdUDP, and FdUTP = fluorodeoxyuridine mono-, di-, and triphosphate, respectively; AIF = acid-insoluble fraction; ND = not detectable.