LTI models for 3-iodothyronamine time dynamics: a multiscale view.

Orsi, Gianni; Frascarelli, Sabina; Zucchi, Riccardo; Vozzi, Giovanni · IEEE Trans Biomed Eng · 2011

basic_science · Level V

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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.

Medical subject headings