Hamroun D, Mathieu M N, Clain E, Germani E, Laliberté M F, Laliberté F, Chevillard C
INSERM U.300, Faculté de Pharmacie, Montpellier, France.
J Cardiovasc Pharmacol. 1995;26 Suppl 3:S156-8.
The presence of endothelin (ET) receptors and the nature of the subtype and expression of ET were investigated in the human megakaryoblastic cell line MEG-01. By the RT-PCR procedure, we have shown that both ETA and ETB receptor subtype mRNAs are expressed in the cells. However, binding experiments have shown that the selective ETB receptor antagonist BQ788, but not the selective ETA receptor antagonist BQ123, competes with the specific binding of [125I]ET-1. Using immunocytochemistry, RIA, and RT-PCR Southern blot, we have shown that MEG-01 cells express ET-1. In addition, ET (1-21)-like immunoreactivity was released from the cells into the culture medium, and this release was modulated by thrombin. These data suggest that an ET-1-mediated autocrine loop could occur in the human megakaryoblastic MEG-01 cell line.
我们在人巨核母细胞系MEG-01中研究了内皮素（ET）受体的存在情况、ET亚型的性质及其表达情况。通过逆转录聚合酶链反应（RT-PCR）方法，我们发现细胞中同时表达ETA和ETB受体亚型的信使核糖核酸（mRNA）。然而，结合实验表明，选择性ETB受体拮抗剂BQ788能与[125I]ET-1的特异性结合发生竞争，而选择性ETA受体拮抗剂BQ123则不能。利用免疫细胞化学、放射免疫分析（RIA）和RT-PCR Southern印迹法，我们证明MEG-01细胞表达ET-1。此外，ET（1-21）样免疫反应性从细胞释放到培养基中，且这种释放受凝血酶调节。这些数据表明，在人巨核母细胞MEG-01细胞系中可能存在ET-1介导的自分泌环。
