Blange I, Drvota V, Yen P M, Sylven C
Karolinska Institute, Department of Cardiology, Huddinge University Hospital, Stockholm, Sweden.
Biol Pharm Bull. 1997 Nov;20(11):1123-6. doi: 10.1248/bpb.20.1123.
Little is known about the cardiac expression of different thyroid hormone receptor (TR) isoforms. The aim of the study was to investigate such patterns of TR expression at the protein level in different species and in some human tissues. Western blot analysis with specific polyclonal rabbit antibodies to each TR isoform was performed with samples from myocardium of the left ventricle from man, dog, guinea pig, rat and mouse, as well as with samples from several human tissues such as heart, skeletal muscle, brain, liver and thyroid. The TR alpha 1 isoform was present in all of the species examined. The TR alpha 2 was recognized in human, dog and guinea pig heart, while no such band was recognized in rat and mouse hearts. TR beta 1 was not detected in the human heart but in the other species. Similarly to TR alpha 1, TR beta 2 was detected in all of the species examined. In the human tissues studied, TR alpha 1 was detected in heart and skeletal muscle, whereas TR alpha 2 was found only in the heart. TR beta 1 was not detected in any of the examined human tissues, while TR beta 2 was found in all of them. These results revealed unique distributions of TR variants and they demonstrate common epitopes in TR in the different species. For the first time, the presence of a TR beta 2 isoform has been shown in human tissues. TR isoforms may have a tissue and species specific role in the regulation of gene expression and may in part explain variable tissue effects of thyroid hormones.
关于不同甲状腺激素受体（TR）亚型在心脏中的表达情况，我们所知甚少。本研究的目的是在蛋白质水平上研究不同物种及一些人体组织中TR的表达模式。我们使用针对每种TR亚型的特异性兔多克隆抗体，对来自人类、狗、豚鼠、大鼠和小鼠左心室心肌的样本，以及来自心脏、骨骼肌、脑、肝脏和甲状腺等几种人体组织的样本进行了蛋白质印迹分析。在所检测的所有物种中均存在TRα1亚型。在人类、狗和豚鼠的心脏中可识别出TRα2，而在大鼠和小鼠的心脏中未识别出该条带。在人类心脏中未检测到TRβ1，但在其他物种中可检测到。与TRα1类似，在所有检测的物种中均检测到了TRβ2。在研究的人体组织中，在心脏和骨骼肌中检测到了TRα1，而TRα2仅在心脏中发现。在所检测的任何人体组织中均未检测到TRβ1，而在所有组织中均发现了TRβ2。这些结果揭示了TR变体的独特分布，并证明了不同物种TR中存在共同表位。首次在人体组织中显示了TRβ2亚型的存在。TR亚型可能在基因表达调控中具有组织和物种特异性作用，并且可能部分解释甲状腺激素的组织效应差异。
