TABLE 1

In Vitro Phosphorylation Rate and Cellular Uptake of Radiolabeled Choline Analogs

Tracer	In vitro phosphorylation* (%)	Uptake by PC-3 cancer cells (% dose/2 h/10⁵ cells plated)
Tracer	In vitro phosphorylation* (%)	Control	HC-3 (5 mmol/L)
CH	55.9 ± 11.0	1.88 ± 0.25	1.04 ± 0.11
FCH	62.0 ± 8.8	1.58 ± 0.18	0.18 ± 0.02
FMEC	55.2 ± 6.6	0.74 ± 0.04^†	0.12 ± 0.02
FEC	43.4 ± 3.4^†	0.32 ± 0.05^†	NA
FPC	22.1 ± 3.1^†	1.29 ± 0.28	0.76 ± 0.20

↵* Tracers incubated in 1 μmol/L choline and 25 mU/mL yeast CK at 23°C for 10 min (n = 5 samples each).
↵† P < 0.01 vs. FCH.
NA = not available.