Identification of thyroid hormone receptor isoforms in thyrotropin-releasing hormone neurons of the hypothalamic paraventricular nucleus.
Identification of thyroid hormone receptor isoforms in thyrotropin-releasing hormone neurons of the hypothalamic paraventricular nucleus.
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DOI：
10.1210/endo.135.1.7516871
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发表时间：
1994-07
期刊：
影响因子：
4.8
通讯作者：
R. Lechan;Yanping Qi;I. Jackson;V. Mahdavi
中科院分区：
文献类型：
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作者：
R. Lechan;Yanping Qi;I. Jackson;V. Mahdavi
下丘脑室旁核（PVN）促垂体神经元中TRH基因的表达受血流中甲状腺激素的调节。为了确定甲状腺激素是否可以直接作用于室旁核中产生TRH的神经元，通过免疫细胞化学双标记技术，使用针对每个功能性TR（TR α 1、TR β 1和TR β 2）的特异性抗血清，然后使用针对前TRH原-（25-50）的抗血清作为TRH神经元的标记物，来确定这些神经元中甲状腺激素受体（TR）的存在。此外，在这些细胞中寻找TR变体TR α 2的存在。免疫反应性TR α 1和TR β 2在室旁核TRH神经元中的比例最高（91.1 +/- 2.5%和83.8 +/- 2.1%），并在核中强烈染色。在大多数TRH神经元中也发现了免疫反应性TR β 1，但与其他TR相比，PVN细胞仅轻微染色。TR α 2被发现仅在PVN中的少数TRH神经元中共存，并且与其在大脑其他区域中更强烈的标记相比，其在细胞核中也有轻微的免疫染色。我们的结论是，垂体TRH神经元含有功能性TRs，因此，这些神经元可能直接受到甲状腺激素的影响。这些细胞中TR α 2的相对缺乏可能有助于TRH神经元对甲状腺激素循环水平影响的选择性。
TRH gene expression in hypophysiotropic neurons of the hypothalamic paraventricular nucleus (PVN) is under regulation by thyroid hormone circulating in the bloodstream. To determine whether thyroid hormone could exert effects directly on TRH-producing neurons in the PVN, the presence of thyroid hormone receptors (TR) in these neurons was determined by double labeling immunocytochemical techniques, using specific antiserum to each of the functional TRs, TR alpha 1, TR beta 1, and TR beta 2, followed by antiserum to prepro-TRH-(25-50) as a marker for TRH neurons. In addition, the presence of the TR variant, TR alpha 2, was sought in these cells. Immunoreactive TR alpha 1 and TR beta 2 were found in the greatest percentage of TRH neurons in the PVN (91.1 +/- 2.5% and 83.8 +/- 2.1%) and intensely stained the nucleus. Immunoreactive TR beta 1 was also found in the majority of TRH neurons, but stained PVN cells only lightly compared to the other TRs. TR alpha 2 was found to coexist in only a minority of TRH neurons in the PVN and also lightly immunostained the nucleus compared to its more intense labeling in other regions of the brain. We conclude that hypophysiotropic TRH neurons contain functional TRs, and therefore, these neurons could be directly influenced by thyroid hormone. The relative paucity of TR alpha 2 in these cells could contribute to the selectivity of this population of TRH neurons to the effects of circulating levels of thyroid hormone.