Estrogen acutely stimulates nitric oxide synthase activity in fetal pulmonary artery endothelium
Estrogen acutely stimulates nitric oxide synthase activity in fetal pulmonary artery endothelium
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DOI：
10.1152/ajplung.1997.273.1.l119
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发表时间：
1997-07-01
影响因子：
4.9
通讯作者：
Shaul, PW
中科院分区：
文献类型：
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作者：
LantinHermoso, RL;Rosenfeld, CR;Shaul, PW
雌激素(E)在某些血管床中具有一氧化氮（NO）介导的作用，胎儿E水平随着分娩而急剧升高，提示E可能参与了出生时一氧化氮介导的肺血管舒张。我们通过测量完整细胞中L-[H-3]精氨酸向L-[H-3]瓜氨酸的转化，验证了E急性刺激羊胎儿肺动脉内皮细胞（PAEC） NO合成酶（NOS）活性的假设。当阈值浓度为10(-10)m时，17 β -雌二醇（E-2 β）存在时，NOS活性呈剂量依赖性上升，增加70-100%。这种效应在E-2 β暴露后5分钟内可检测到，其最大反应与阈值浓度为10(-8)m的乙酰胆碱相当。Ca2+去除完全抑制E-2 β刺激的NOS活性，E-2 β和Ca2+离子通道a- 23187的活性不是加性的。此外，NOS内皮亚型（eNOS）的表达未发生改变，免疫印迹分析未检测到诱导型和神经元型NOS亚型。这些发现表明E-2 β通过Ca2+内流剧烈刺激eNOS。此外，E-2 β刺激的NOS活性被E受体（ER）拮抗剂他莫昔芬和ici - 182780完全抑制，逆转录-聚合酶链反应中ER mRNA表达明显。因此，E通过内皮ER的激活和细胞内Ca2+的增加，急性刺激胎儿PAEC中eNOS的活性。
Estrogen (E) has nitric oxide (NO)-mediated effects in certain vascular beds, and fetal E levels rise acutely with parturition, suggesting that E may be involved in NO-mediated pulmonary vasodilation at birth. We tested the hypothesis that E acutely stimulates NO synthase (NOS) activity in ovine fetal pulmonary artery endothelial cells (PAEC) by measuring L-[H-3]arginine conversion to L-[H-3]citrulline in intact cells. NOS activity in the presence of 17 beta-estradiol (E-2 beta) rose in a dose-dependent manner, increasing 70-100%, with a threshold concentration of 10(-10) M. This effect was detectable within 5 min of E-2 beta exposure, and the maximal response was comparable to that obtained with acetylcholine, which had a threshold concentration of 10(-8) M. Ca2+ removal completely inhibited E-2 beta-stimulated NOS activity, and activity with E-2 beta and the Ca2+ ionophore A-23187 was not additive. In addition, the expression of the endothelial isoform of NOS (eNOS) was not altered, and the inducible and neuronal NOS isoforms were not detected by immunoblot analysis. These findings indicate that E-2 beta acutely stimulates eNOS by Ca2+ influx. Furthermore, E-2 beta-stimulated NOS activity was fully inhibited by the E receptor (ER) antagonists tamoxifen and ICI-182,780, and ER mRNA expression was evident in reverse transcription-polymerase chain reaction assays. Thus E acutely stimulates eNOS activity in fetal PAEC via the activation of endothelial ER and increases in intracellular Ca2+.