UPTAKE AND LIFE TIME OF FLUORIDE-ION IN RATS BY F-19-NMR

F-19 nuclear magnetic resonance (NMR) was utilized to obtain informati on on the uptake and half-life time of fluoride ion in rats. Changes i n tissue fluoride level after acute loading were monitored over time i n blood and tissue homogenates obtained from liver and brain. The rate of fluoride elimination from various tissues was roughly similar, fol lowing in all cases a first-order kinetic rate law. The F- concentrati on in brain was about 20% of that found in liver, indicating a reduced fluoride diffusion across the blood-brain barrier. In vivo F- spectra were obtained in rat brain in few minutes with a good signal-to-noise ratio; this confirms the possibility of extending the use of F- as a probe of biomolecules to in vivo applications.