Badr K F, Munger K A, Sugiura M, Snajdar R M, Schwartzberg M, Inagami T
Department of Medicine, Vanderbilt University School of Medicine, Nashville, TN 37232-2372.
Biochem Biophys Res Commun. 1989 Jun 15;161(2):776-81. doi: 10.1016/0006-291x(89)92667-3.
Endothelin contracts glomerular mesangial cells, thereby influencing glomerular size and filtration rate. Here, we demonstrate the presence of two ET-specific binding sites on cultured rat mesangial cells with Kds of 0.76 and 44.70 nM, and maximal binding capacity (Bmax) values of 6.78 x 10(2) and 27.60 x 10(2) binding sites/cell, respectively. Binding of [125I]-ET was maximal at 120 min at 4 degrees C, stable for the subsequent 60 min, and selective. No competition for binding was observed with greater than 1000-fold concentrations of atrial natriuretic peptide, angiotensin II, arginine vasopressin, nicardipine, or nifedipine. The presence of specific receptors for ET on glomerular mesangial cells suggests a major role for this peptide in the regulation of glomerular filtration rate.
内皮素可使肾小球系膜细胞收缩，从而影响肾小球大小和滤过率。在此，我们证明培养的大鼠系膜细胞上存在两个内皮素特异性结合位点，其解离常数（Kd）分别为0.76和44.70 nM，最大结合容量（Bmax）值分别为6.78×10²和27.60×10²个结合位点/细胞。[¹²⁵I]-内皮素的结合在4℃下120分钟时达到最大值，在随后的60分钟内保持稳定，且具有选择性。在浓度高于心房利钠肽、血管紧张素II、精氨酸加压素、尼卡地平或硝苯地平1000倍的情况下，未观察到结合竞争。肾小球系膜细胞上内皮素特异性受体的存在表明该肽在调节肾小球滤过率中起主要作用。
