title: Quantification of thyroxine and 3,5,3'-triiodo-thyronine in human and animal hearts by a novel liquid chromatography-tandem mass spectrometry method.
abstract: Assaying tissue T3 and T4 would provide important information in experimental and clinical investigations. A novel method to determine tissue T3 and T4 by HPLC coupled to mass spectrometry is described. The major difference vs. previously described methods lies in the addition of a derivatization step, that is, to convert T3 and T4 into the corresponding butyl esters. The yield of esterification was ̴ 100% for T3 and 80% for T4. The assay was linear (r>0.99) in the range of 0.2-50 ng/ml, accuracy was in the order of 70-75%, and the minimum tissue amount needed was in the order of 50 mg, that is, about one order of magnitude lower than observed with the same equipment (AB Sciex API 4000 triple quadrupole mass spectrometer) if derivatization was omitted. The method allowed detection of T3 and T4 in human left ventricle biopsies yielding concentrations of 1.51±0.16 and 5.94±0.63 pmol/g, respectively. In rats treated with different dosages of exogenous T3 or T4, good correlations (r>0.90) between plasma and myocardial T3 and T4 concentrations were observed, although in specific subsets different plasma T4 concentrations were not associated with different tissue content in T4. We conclude that this method could provide a novel insight into the relationship between plasma and tissue thyroid hormone levels.
authors.affiliation: Department of Pathology, University of Pisa, Pisa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Saba
authors.affiliation: Department of Pathology, University of Pisa, Pisa, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Donzelli
authors.affiliation: Department of Medicine, University of Pisa, Pisa, Italy.
authors.forename: D
authors.initials: D
authors.lastname: Colligiani
authors.affiliation: National Research Council, Institute of Clinical Physiology, Pisa, Italy.
authors.forename: A
authors.initials: A
authors.lastname: Raffaelli
authors.affiliation: Department of Medicine, University of Pisa, Pisa, Italy.
authors.forename: M
authors.initials: M
authors.lastname: Nannipieri
authors.affiliation: National Research Council, Institute of Clinical Physiology, Pisa, Italy.
authors.forename: C
authors.initials: C
authors.lastname: Kusmic
authors.affiliation: Muscle Research Unit, Bosch Institute, The University of Sydney, Sydney, Australia.
authors.forename: C G
authors.initials: CG
authors.lastname: Dos Remedios
authors.affiliation: Laboratory for Physiology, Institute for Cardiovascular Research, VU -University Medical Center, Amsterdam, The Netherlands.
authors.forename: W S
authors.initials: WS
authors.lastname: Simonides
authors.affiliation: National Research Council, Institute of Clinical Physiology, Pisa, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Iervasi
authors.affiliation: Department of Pathology, University of Pisa, Pisa, Italy.
authors.forename: R
authors.initials: R
authors.lastname: Zucchi
mesh_terms: D000818:Animals; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006801:Humans; D009206:Myocardium / Q000737:chemistry* / Q000378:metabolism; D017208:Rats, Wistar; D053719:Tandem Mass Spectrometry / Q000379:methods*; D013974:Thyroxine / Q000032:analysis* / Q000378:metabolism; D014284:Triiodothyronine / Q000032:analysis* / Q000378:metabolism
chemical_list: D014284:Triiodothyronine; D013974:Thyroxine