N- and O-Acetylated 3-Iodothyronamines Have No Metabolic or Thermogenic Effects in Male Mice

Sogol Gachkar; Rebecca Oelkrug; Beate Herrmann; Thomas S Scanlan; Qian Sun; Heike Biebermann; Carolin S Hoefig; Lutz Schomburg; Jens Mittag

doi:10.1159/000504887

N- and O-Acetylated 3-Iodothyronamines Have No Metabolic or Thermogenic Effects in Male Mice

Eur Thyroid J. 2020 Feb;9(2):57-66. doi: 10.1159/000504887. Epub 2019 Dec 20.

Authors

Sogol Gachkar¹, Rebecca Oelkrug¹, Beate Herrmann¹, Thomas S Scanlan², Qian Sun³, Heike Biebermann⁴, Carolin S Hoefig³, Lutz Schomburg³, Jens Mittag¹

Affiliations

¹ Molecular Endocrinology, Center of Brain, Behavior and Metabolism, University of Lübeck, Lübeck, Germany.
² Department of Physiology and Pharmacology, Oregon Health and Science University, Portland, Oregon, USA.
³ Institute for Experimental Endocrinology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.
⁴ Institute of Experimental Pediatric Endocrinology, Charité - Universitätsmedizin Berlin, corporate member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany.

Abstract

Introduction: Injection of 3-iodothyronamine into experimental animals profoundly affects their metabolism and body temperature. As 3-iodothyronamine is rapidly acetylated in vivo after injection, it was hypothesized that the metabolites N- or O-acetyl-3-iodothyronamines could constitute the active hormones.

Methods: Adult male mice were injected once daily with one of the metabolites (5 mg/kg body weight intraperitoneally dissolved in 60% DMSO in PBS) or solvent. Metabolism was monitored by indirect calorimetry, body temperature by infrared thermography, and body composition by nuclear magnetic resonance analysis. Signaling activities in brown fat or liver were assessed by studying target gene transcription by qPCR including uncoupling protein 1 or deiodinase type 1 or 2, and Western blot.

Results: The markers of metabolism, body composition, or temperature tested were similar in the mice injected with solvent and those injected with one of the acetylated 3-iodothyronamines.

Conclusions: In our experimental setup, N- and O-acetyl-3-iodothyronamine do not constitute compounds contributing to the metabolic or temperature effects described for 3-iodothyronamine. The acetylation of 3-iodothyronamine observed in vivo may thus rather serve degradation and elimination purposes.

Keywords: Body temperature; Brown adipose tissue; Metabolism; Thermoregulation; Thyroid hormone; Thyronamines.