title: In vivo assessment of 6-deoxy-6-[18F]fluoro-D-galactose as a PET tracer for studying galactose metabolism.
abstract: The potential of 6-deoxy-6-[18F]fluoro-D-galactose (6-[18F]FdGal) as an in vivo tracer for studying galactose metabolism in tumors and liver was investigated. High uptake and rapid clearance of the radioactivity were observed in many organs of mice after i.v. injection of the tracer. D-Galactose loading did not affect liver uptake. Three experimental tumors showed a slightly higher uptake than other tissues, and rat brain tumor was clearly visualized by autoradiography. However, the radioactivity in tumors decreased rapidly. In the liver, a significant amount of the tracer was found in a galactonate form, while this oxidation was a minor metabolic pathway in the tumors. In both tumor and liver tissues, small amounts of the tracer were incorporated into macromolecular glycoconjugate via phosphate and uridylate forms as intermediate precursors. These results indicate that 6-[18F]FdGal is not suitable for studying galactose metabolism in vivo because of the low affinity of the tracer for the metabolism.
authors.affiliation: Division of Radiopharmaceutical Chemistry, Tohoku University, Sendai, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Ishiwata
authors.forename: M
authors.initials: M
authors.lastname: Tomura
authors.forename: T
authors.initials: T
authors.lastname: Ido
authors.forename: R
authors.initials: R
authors.lastname: Iwata
authors.forename: J
authors.initials: J
authors.lastname: Itoh
authors.forename: M
authors.initials: M
authors.lastname: Kameyama
mesh_terms: D000818:Animals; D001921:Brain / Q000000981:diagnostic imaging / Q000378:metabolism; D005462:Fluorine Radioisotopes; D005643:Fucose / Q000031:analogs & derivatives* / Q000097:blood / Q000493:pharmacokinetics; D005690:Galactose / Q000378:metabolism*; D008099:Liver / Q000000981:diagnostic imaging / Q000378:metabolism; D051379:Mice; D008809:Mice, Inbred C3H; D008810:Mice, Inbred C57BL; D009374:Neoplasms, Experimental / Q000000981:diagnostic imaging; D051381:Rats; D014018:Tissue Distribution; D014055:Tomography, Emission-Computed
chemical_list: D005462:Fluorine Radioisotopes; D005643:Fucose; C037333:6-deoxy-6-fluorogalactose; D005690:Galactose