Department for Diagnostic Laboratory Medicine, Institute for Clinical Chemistry and Pathobiochemistry, University Hospital Tuebingen, Tuebingen, Germany.
Center for Medical Research, Medical University Graz, Graz, Austria.
Front Endocrinol (Lausanne). 2021 Apr 26;12:587518. doi: 10.3389/fendo.2021.587518. eCollection 2021.
Thyroxine and triiodothyronine (T3) are classical thyroid hormones and with relatively well-understood actions. In contrast, the physiological role of thyroid hormone metabolites, also circulating in the blood, is less well characterized. These molecules, namely, reverse triiodothyronine, 3,5-diiodothyronine, 3-iodothyronamine, tetraiodoacetic acid and triiodoacetic acid, mediate both agonistic (thyromimetic) and antagonistic actions additional to the effects of the classical thyroid hormones. Here, we provide an overview of the main factors influencing thyroid hormone action, and then go on to describe the main effects of the metabolites and their potential use in medicine. One section addresses thyroid hormone levels in corona virus disease 19 (COVID-19). It appears that i) the more potently-acting molecules T3 and triiodoacetic acid have shorter half-lives than the less potent antagonists 3-iodothyronamine and tetraiodoacetic acid; ii) reverse T3 and 3,5-diiodothyronine may serve as indicators for metabolic dysregulation and disease, and iii) Nanotetrac may be a promising candidate for treating cancer, and resmetirom and VK2809 for steatohepatitis. Further, the use of L-T3 in the treatment of severely ill COVID-19 patients is critically discussed.
甲状腺素和三碘甲状腺原氨酸（T3）是经典的甲状腺激素，其作用相对明确。相比之下，甲状腺激素代谢产物（也在血液中循环）的生理作用则不太明确。这些分子，如反式三碘甲状腺原氨酸、3,5-二碘甲状腺原氨酸、3-碘甲状腺原氨酸、四碘乙酸和三碘乙酸，除了经典甲状腺激素的作用外，还介导激动剂（甲状腺素类似物）和拮抗剂的作用。在这里，我们提供了一个影响甲状腺激素作用的主要因素概述，然后描述代谢产物的主要作用及其在医学中的潜在用途。有一节专门讨论了新冠病毒疾病 19（COVID-19）中的甲状腺激素水平。似乎有以下几点：i）作用更强的 T3 和三碘乙酸的半衰期比作用较弱的拮抗剂 3-碘甲状腺原氨酸和四碘乙酸短；ii）反式三碘甲状腺原氨酸和 3,5-二碘甲状腺原氨酸可能作为代谢失调和疾病的指标；iii）纳米四可能是治疗癌症的有前途的候选物，雷美替胺和 VK2809 可能是治疗脂肪性肝炎的候选物。此外，还对 L-T3 在治疗重症 COVID-19 患者中的应用进行了批判性讨论。
