title: Distribution of exogenous [125I]-3-iodothyronamine in mouse in vivo: relationship with trace amine-associated receptors.
abstract: 3-Iodothyronamine (T1AM) is a novel chemical messenger, structurally related to thyroid hormone, able to interact with G protein-coupled receptors known as trace amine-associated receptors (TAARs). Little is known about the physiological role of T1AM. In this prospective, we synthesized [125I]-T1AM and explored its distribution in mouse after injecting in the tail vein at a physiological concentration (0.3 nM). The expression of the nine TAAR subtypes was evaluated by quantitative real-time PCR. [125I]-T1AM was taken up by each organ. A significant increase in tissue vs blood concentration occurred in gallbladder, stomach, intestine, liver, and kidney. Tissue radioactivity decreased exponentially over time, consistent with biliary and urinary excretion, and after 24 h, 75% of the residual radioactivity was detected in liver, muscle, and adipose tissue. TAARs were expressed only at trace amounts in most of the tissues, the exceptions being TAAR1 in stomach and testis and TAAR8 in intestine, spleen, and testis. Thus, while T1AM has a systemic distribution, TAARs are only expressed in certain tissues suggesting that other high-affinity molecular targets besides TAARs exist.
authors.affiliation: Dipartimento di Scienze dell'Uomo e dell'Ambiente, University of Pisa, Via Roma 55, 56126 Pisa, Italy. g.chiellini@bm.med.unipi.it
authors.forename: Grazia
authors.initials: G
authors.lastname: Chiellini
authors.forename: Paola
authors.initials: P
authors.lastname: Erba
authors.forename: Vittoria
authors.initials: V
authors.lastname: Carnicelli
authors.forename: Chiara
authors.initials: C
authors.lastname: Manfredi
authors.forename: Sabina
authors.initials: S
authors.lastname: Frascarelli
authors.forename: Sandra
authors.initials: S
authors.lastname: Ghelardoni
authors.forename: Giuliano
authors.initials: G
authors.lastname: Mariani
authors.forename: Riccardo
authors.initials: R
authors.lastname: Zucchi
mesh_terms: D000818:Animals; D005753:Gastric Mucosa / Q000378:metabolism; D020869:Gene Expression Profiling; D007275:Injections, Intravenous; D007413:Intestinal Mucosa / Q000378:metabolism; D007457:Iodine Radioisotopes; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013154:Spleen / Q000378:metabolism; D013737:Testis / Q000378:metabolism; D013970:Thyronines / Q000008:administration & dosage / Q000378:metabolism / Q000493:pharmacokinetics*; D014018:Tissue Distribution; D000095383:Trace Amine-Associated Receptors
chemical_list: D007457:Iodine Radioisotopes; D043562:Receptors, G-Protein-Coupled; D013970:Thyronines; D000095383:Trace Amine-Associated Receptors; C487948:3-iodothyronamine; C574154:Taar8a protein, mouse; C574155:Taar8a protein, rat