Specific [125I]brain natriuretic peptide-26 binding sites in rat and pig kidneys.
Specific binding sites for porcine brain natriuretic peptide-26 (BNP-26), a member of the atrial natriuretic peptide family (ANPs), were investigated in the kidney by using receptor autoradiographic and membrane binding techniques with [125I]BNP-26. The binding sites were discretely localized in rat and porcine kidney areas corresponding anatomically to the glomeruli and inner medulla. There were no differences between the localization of [125I]BNP-26 and [125I]alpha-rat ANP binding sites in the kidney. [125I]BNP-26 binding to solubilized membranes from isolated glomeruli of the rat kidney was saturable, and a single class of high-affinity sites was labeled with a KD of 372 pM. The radioligand bound to two sites in solubilized inner medullary membranes of the rat, a low-affinity site with a KD of 30 nM, and a high-affinity site with a KD of 33 pM. The rank order of potency to inhibit binding was BNP-26 = alpha-rat ANP-(1-28) greater than atriopeptin III (ANP-(103-126)) much greater than atriopeptin I (ANP-(103-123)) greater than des-Cys105,Cys121- ANP-(104-126). Thus, [125I]BNP-26 presumably recognizes ANP receptors in the kidney. The possibility that BNP-26 regulates, as a circulating hormone, kidney functions by binding to ANP receptors would have to be considered.
Maeda
T
T
Department of Pharmacology, Nagasaki University School of Medicine, Japan.
Niwa
M
M
Shigematsu
K
K
Kurihara
M
M
Kataoka
Y
Y
Nakao
K
K
Imura
H
H
Matsuo
H
H
Tsuchiyama
H
H
Ozaki
M
M
D000818:Animals; D009320:Atrial Natriuretic Factor / Q000378:metabolism*; D001345:Autoradiography; D001667:Binding, Competitive; D007457:Iodine Radioisotopes; D007668:Kidney / Q000378:metabolism*; D007678:Kidney Glomerulus / Q000378:metabolism; D007679:Kidney Medulla / Q000378:metabolism; D007700:Kinetics; D008297:Male; D020097:Natriuretic Peptide, Brain; D009419:Nerve Tissue Proteins / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains; D017461:Receptors, Atrial Natriuretic Factor; D011956:Receptors, Cell Surface / Q000378:metabolism*; D013045:Species Specificity; D013552:Swine; D013696:Temperature
D007457:Iodine Radioisotopes; D009419:Nerve Tissue Proteins; D011956:Receptors, Cell Surface; C058930:brain natriuretic peptide receptor; D020097:Natriuretic Peptide, Brain; D009320:Atrial Natriuretic Factor; D017461:Receptors, Atrial Natriuretic Factor