Ishihara T, Kato J, Kitamura K, Katoh F, Fujimoto S, Kangawa K, Eto T
First Department of Internal Medicine, Miyazaki Medical College, Kiyotake, Japan.
Life Sci. 1997;60(20):1763-9. doi: 10.1016/s0024-3205(97)00136-7.
To examine the production of adrenomedullin (AM) in human vascular endothelial cells, AM concentrations in cultured endothelial cells derived from the human umbilical vein and the conditioned media of the cells were measured in the present study. The cultured endothelial cells secreted immunoreactive AM (ir-AM) into the medium at a rate of 14.7 +/- 3.0 fmol/10(6) cells/24 h with an intracellular ir-AM of 5.2 +/- 0.8 fmol/l0(6) cells. Analysis by reverse phase high performance-liquid chromatography (HPLC) showed that ir-AM in both the cells and the conditioned medium eluted at the position identical to that of human AM(1-52). Treatment with dexamethasone significantly augmented the secretion of ir-AM from the cells without any effect on the intracellular ir-AM concentration. Northern blot analysis showed not only the presence of the 1.6 kb human AM precursor mRNA in the endothelial cells, but also its increased expression in the dexamethasone-treated cells. Thus, AM was synthesized and secreted by the human endothelial cells of the umbilical vein, and glucocorticoid augmented the AM production. These findings suggest not only the role of AM as a local modulator of the vascular tone but also the possibility that endothelial cells contribute to circulating AM in the human blood.
为检测人血管内皮细胞中肾上腺髓质素（AM）的产生，本研究测定了源自人脐静脉的培养内皮细胞及其条件培养基中的AM浓度。培养的内皮细胞以14.7±3.0 fmol/10⁶细胞/24小时的速率向培养基中分泌免疫反应性AM（ir-AM），细胞内ir-AM为5.2±0.8 fmol/10⁶细胞。反相高效液相色谱（HPLC）分析表明，细胞和条件培养基中的ir-AM在与人AM（1-52）相同的位置洗脱。地塞米松处理显著增加了细胞中ir-AM的分泌，但对细胞内ir-AM浓度没有影响。Northern印迹分析表明，内皮细胞中不仅存在1.6 kb的人AM前体mRNA，而且在地塞米松处理的细胞中其表达增加。因此，人脐静脉内皮细胞合成并分泌AM，糖皮质激素增加了AM的产生。这些发现不仅提示了AM作为血管张力局部调节剂的作用，还提示了内皮细胞对人血液中循环AM有贡献的可能性。
