甲状腺激素受体 (TRs)是细胞核受体 ,广泛分布于大多数组织中。TRs包括两类异构体TRα(TRα1 ,TRα2 ,TRα3,TRΔα1 和TRΔα2 )和TRβ(TRβ1 ,TRβ2 ,TRβ3和TRΔβ3)。有 4种功能性TR异构体 (TRα1 ,TRβ1 ,TRβ2 ,TRβ3)。其余的TRs异构体无受体功能 ,有受体拮抗剂的作用。TRα的主要功能是调节机体的生长发育 ,维持甲状腺功能。而TRβ可增加机体对T3的敏感性 ,保持听力正常 ,维持甲状腺激素 (TH )对促甲状腺激素 (TSH)的负反馈调节。心脏主要为TRα1 分布 ,肝脏主要为TRβ1 分布。TRβ2 的mRNA表达多限于脑垂体和丘脑下部。TH对心肌功能起着重要调节作用。T3对于心脏病合并低T3综合征的治疗具有临床意义。T4 衍生物二碘甲状腺丙酸增加心肌收缩力而对机体代谢影响很小。与之相对 ,T3衍生物三碘甲状腺氧乙酸具有降血脂 ,治疗肥胖的作用而不影响心功能或心率 Thyroid hormone receptors (TRs) are nuclear receptors widely distributed in most tissues. TRs include two classes of isomers TRα (TRα1, TRα2, TRα3, TRΔα1 and TRΔα2) and TRβ (TRβ1, TRβ2, TRβ3 and TRΔβ3). There are four functional TR isoforms (TRα1, TRβ1, TRβ2, TRβ3). The remaining TRs isomer has no receptor function and receptor antagonist effect. TRα’s main function is to regulate the body’s growth and development, to maintain thyroid function. TRβ can increase the body’s sensitivity to T3, maintain normal hearing, and maintain the negative feedback regulation of thyroid hormone (TH) on thyroid-stimulating hormone (TSH). The heart mainly TRα1 distribution, the liver mainly TRβ1 distribution. TRβ2 mRNA expression is mostly limited to the pituitary and hypothalamus. TH plays an important regulatory role on myocardial function. T3 for the treatment of heart disease with low T3 syndrome has clinical significance. T4 derivatives of iodine thyroid propionate increased myocardial contractility and metabolism of the body has little effect. In contrast, the T3 derivative triiodothyronine has the effect of lowering blood fat and treating obesity without affecting heart function or heart rate