High and low affinity binding sites for endothelin on cultured rat glomerular mesangial cells

• Published in: Biochemical and biophysical research communications Vol. 161; no. 2; pp. 776 - 781
• Main Authors: Badr, Kamal F., Munger, Karen A., Sugiura, Masanori, Snajdar, Rudolf M., Schwartzberg, Mindy, Inagami, Tadashi
• Format: Journal Article
• Language: English
• Published: San Diego, CA Elsevier Inc 15.06.1989; Elsevier
• Subjects: Animals; Biological and medical sciences; Cell receptors; Cell structures and functions; Cells, Cultured; endothelin; Endothelins; Fundamental and applied biological sciences. Psychology; Glomerular Mesangium - metabolism; Kinetics; Molecular and cellular biology; Peptides - metabolism; Rats; Receptors, Cell Surface - metabolism; Receptors, Endothelin; arginine vasopressin; Endothelin; intracellular calcium concentration; inositol-(1,4,5)-trisphosphate; angiotensin II; atrial natriuretic factor; Cell culture; Vertebrata; Mammalia; Radiolabelling; Peptides; Rat; Mesangial cell; Rodentia; Glomerulus; Scatchard plot; Binding site
• ISSN: 0006-291X; 1090-2104
• 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 6.78×10 2 and 27.60×10 2 binding sites/cell, respectively. Binding of [ 125I]-ET was maximal at 120 min at 4°C, stable for the subsequent 60 min, and selective. No competition for binding was observed with >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.