title: LTI models for 3-iodothyronamine time dynamics: a multiscale view.
abstract: 3-Iodothyronamine (T(1)AM) is a novel relative of thyroid hormone that plays a role in critical body regulatory processes such as glucose metabolism, thermal regulation, and heart beating. This paper was aimed at characterizing time dynamics of T(1)AM and its catabolite 3-iodothyroacetic acid (TA(1)) in different biological scales with linear time-invariant models. Culture medium samples coming from culture of H9c2 murine cells and perfusion liquid samples from perfused rat heart were collected after the injection of a T(1)AM bolus. T(1)AM and TA(1) concentrations in the samples were assayed with high-performance liquid chromatography coupled to tandem mass spectrometry. Kinetic constants relative to T(1)AM transport and conversion were estimated with weighted least-squares method. We found that these constants can be related with an allometric power law depending on mass, with a negative exponent of -0.27 ± 0.19, implying that the velocity of conversion and internalization of T(1)AM decreases with increasing of system mass.
authors.affiliation: Interdepartmental Research Center E. Piaggio, Faculty of Engineering, University of Pisa, 56126 Pisa, Italy. orsigianni@gmail.com
authors.forename: Gianni
authors.initials: G
authors.lastname: Orsi
authors.forename: Sabina
authors.initials: S
authors.lastname: Frascarelli
authors.forename: Riccardo
authors.initials: R
authors.lastname: Zucchi
authors.forename: Giovanni
authors.initials: G
authors.lastname: Vozzi
mesh_terms: D000818:Animals; D002460:Cell Line; D002851:Chromatography, High Pressure Liquid; D006321:Heart / Q000502:physiology; D007700:Kinetics; D016018:Least-Squares Analysis; D016014:Linear Models; D008297:Male; D051379:Mice; D008954:Models, Biological; D032386:Myoblasts, Cardiac / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D010477:Perfusion; D051381:Rats; D017208:Rats, Wistar; D053719:Tandem Mass Spectrometry; D013970:Thyronines / Q000378:metabolism*
chemical_list: C487948:3-iodothyronamine; D013970:Thyronines