Thyronamines are exciting new players at the crossroads of thyroidology and metabolism. Here, we report the development of a method to measure 3-iodothyronamine (T(1)AM) and thyronamine (T(0)AM) in plasma and tissue samples. The detection limit of the method was 0.25 nmol/l in plasma and 0.30 pmol/g in tissue both for T(1)AM and for T(0)AM. Using this method, we were able to demonstrate T(1)AM and T(0)AM in plasma and liver from rats treated with synthetic thyronamines. Although we demonstrated the in vivo conversion of (13)C(6)-thyroxine ((13)C(6)-T(4)) to (13)C(6)-3,5,3'-triiodothyronine, we did not detect (13)C(6)-T(1)AM in plasma or brain samples of rats treated with (13)C(6)-T(4). Surprisingly, our method did not detect any endogenous T(1)AM or T(0)AM in plasma from vehicle-treated rats, nor in human plasma or thyroid tissue. Although we are cautious to draw general conclusions from these negative findings and in spite of the fact that insufficient sensitivity of the method related to extractability and stability of T(0)AM cannot be completely excluded at this point, our findings raise questions on the biosynthetic pathways and concentrations of endogenous T(1)AM and T(0)AM.
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http://dx.doi.org/10.1677/JOE-10-0060 | DOI Listing |
Exp Clin Endocrinol Diabetes
June 2020
Charité - Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, Berlin, Germany Institut für Experimentelle Endokrinologie, Berlin, Germany.
Thyroid hormone metabolites (THM) with few or no iodine substituents such as 3,5-T2, the thyronamines 3-T1AM and T0AM, and their oxidation products, the thyroacetic acids (TA) formed by monoamine oxidases, have recently attracted major interest due to their metabolic actions which are in part distinct from those of the classical thyromimetic hormone T3, the major ligand of T3 receptors. This review compiles and discusses effects of 3,5-T2, TAM and TA reported for thyrocytes, pancreatic islets and hepatocytes as well as findings from studies in mouse models after single or repeated administration of pharmacological doses of these agents. Comparison of the 3,5-T2 effects on the transcriptome with not yet published proteome data in livers of obese mice on high fat diet indicate a distinct anti-steatotic effect of this THM.
View Article and Find Full Text PDFTalanta
March 2019
REQUIMTE/LAQV, Instituto Superior de Engenharia do Porto (ISEP), Politécnico do Porto, Rua Dr. António Bernardino de Almeida 431, 4200-072 Porto, Portugal.
Recent studies have shown that besides the well-known T (triiodothyronine) and T (thyroxine) there might be other important thyroid hormones, in particular TAM (thyronamine) and TAM (3-iodothyronamine). The absence of a large number of studies showing their precise importance might be explained by the limited number of analytical methodologies available. This work aims to show an electroanalytical alternative making use of electropolymerized molecularly imprinted polymer (MIPs).
View Article and Find Full Text PDFThyroid
October 2018
1 Department of Neurology, Psychology, Drug Sciences, and Child Health, Pharmacology Division; Division of Clinical Pharmacology and Oncology; University of Florence, Florence, Italy .
Background: 3-Iodothyroacetic acid (TA1) is among the thyroid hormone (T3) metabolites that can acutely modify behavior in mice. This study aimed to investigate whether TA1 is also able to reduce neuron hyper-excitability and protect from excitotoxic damage.
Methods: CD1 male mice were treated intraperitoneally with saline solution or TA1 (4, 7, 11, or 33 μg/kg) before receiving 90 mg/kg pentylenetrazole subcutaneously.
Endocr Connect
May 2018
Department of Obstetrics and GynecologyUniversity Hospital, LMU Munich, Munich, Germany.
Objectives: l-dopa decarboxylase (DDC) is responsible for the synthesis of dopamine. Dopamine, which binds to the D-dopamine receptor (D2R), plays an important role in the maintenance of pregnancy. Aim of our study was the analysis of DDC and D2R expression in placentas of spontaneous miscarriages (SMs) and recurrent miscarriages (RMs) in comparison to healthy controls.
View Article and Find Full Text PDFPLoS One
October 2017
Charité-Universitätsmedizin Berlin, Institut für Experimentelle Endokrinologie, Augustenburger Platz 1, Berlin, Germany.
Tyrosine and phenolic ring de-iodination of thyroid hormones (TH) is crucial for regulating their physiological activity. Furthermore, reactions such as de-carboxylation to thyronamines (TAM) and de-amination to thyroacetic acids (TAc) produce TH metabolites (THM) with distinct biological properties. This needs to be considered when studying effects of TH and THM.
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