Atrial natriuretic peptide binding properties of purified rat glomerular membranes.
125I-ANP (3-[125I] iodotyrosyl28) binding studies with purified rat glomerular membranes indicate two types of physiologically relevant hormonal receptors, Types I and II, Kd approximately 5 pM and approximately 2.5 nM, respectively. All preparations were essentially free of capsular and tubular contamination. Binding data indicated that Type I receptors were three times more concentrated than Type II receptors in purified membrane fractions. When purified membranes were cross-linked with 125I-rANP, using disuccinimidyl suberate and separated by SDS-PAGE, approximately 75- and approximately 140-kDa proteins were specifically labeled in a ratio of approximately 3:1, respectively. Thus, in purified renal glomerular membranes, Type I receptors with molecular weight of approximately 75-kDa appeared to predominate and would be detectably saturated at circulating ANP concentrations as low as 15 pg/ml. These findings could account for the exquisite sensitivity of natriuretic response to ANP.
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001345:Autoradiography; D004591:Electrophoresis, Polyacrylamide Gel; D066298:In Vitro Techniques; D007678:Kidney Glomerulus / Q000378:metabolism*; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D011869:Radioligand Assay; D051381:Rats; D011919:Rats, Inbred Strains; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000378:metabolism*
D011956:Receptors, Cell Surface; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor