beta-fluoromethylene-3-tyrosine has been researched along with Neuroendocrine-Tumors* in 1 studies
1 other study(ies) available for beta-fluoromethylene-3-tyrosine and Neuroendocrine-Tumors
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Aromatic L-amino acid decarboxylase (AAAD) inhibitors as carcinoid tumor-imaging agents: synthesis of 18F-labeled alpha-fluoromethyl-6-fluoro-m-tyrosine (FM-6-FmT).
The aromatic L-amino acid decarboxylase (AAAD) enzyme is significantly upregulated in neuroendocrine tumors and, thus, would be a good target for PET imaging agents. Alpha-fluoromethyl-DOPA (FMDOPA) is one of the most potent irreversible AAAD inhibitor and its non-catechol derivative, alpha-fluoromethyl-m-tyrosine (FMmT), is a promising AAAD imaging agent. We synthesized FMmT and its direct electrophilic fluorination provided a mixture of products identified by NMR analysis after HPLC purification as 6-fluoro-, 2-fluoro- and 2,6-difluoro-derivatives of FMmT. Using rat striatal homogenates, alpha-fluoromethyl-6-fluoro-m-tyrosine (FM-6-FmT) was found to have AAAD inhibitory activity comparable to that of FMDOPA. Electrophilic radiofluorination of FMmT using [18F]AcOF gave 18F labeled 6-fluoro-, 2-fluoro- and 2,6-difluoro-FMmT derivatives in 22.0%, 21.9% and 8.5% radiochemical yields, respectively. Based on its proposed mechanism of inhibition, FM-6-[18F]FmT is expected to irreversibly bind to AAAD and, hence, could be used as a PET agent to image tumors of endocrine origin containing high concentrations of AAAD. Since FM-6-FmT lacks the catechol moiety, it is expected to be better than FMDOPA since it is not a substrate for catechol-O-methyltransferase. Topics: Aromatic Amino Acid Decarboxylase Inhibitors; Aromatic-L-Amino-Acid Decarboxylases; Carcinoid Tumor; Fluorine Radioisotopes; Humans; Isotope Labeling; Neuroendocrine Tumors; Protein Binding; Radioligand Assay; Radiopharmaceuticals; Tomography, Emission-Computed; Tyrosine | 2003 |