PET STUDY OF THE DISTRIBUTION OF [C-11] FLUOXETINE IN A MONKEY BRAIN

No-carrier-added [C-11]fluoxetine (2) was synthesized by methylation o f norfluoxetine (1) with [C-11]H3I in 20% radiochemical yield in a syn thesis time of 40 min from EOB with a specific activity of 0.48 Ci/mu M (EOB). In vivo study in mouse indicated that the uptake of 2 in mous e tissues was high and the radioactivity remained constant throughout the study. The uptake of 2 in mouse brain was 4%/g. PET study in a Rhe sus monkey also showed that the uptakes of 2 in different brain region s were similar and the retention of radioactivity in these regions rem ained constant throughout the study (80 min). Analysis of arterial pla sma by HPLC showed that only 20% of radioactivity in the plasma remain ed as 2 at 30 min post-injection. These results suggest that the uptak e of fluoxetine in monkey brain is probably not receptor mediated. Rat her, blood flow, lipophilicity or other transport mechanisms may play a role in its uptake.