Maeda T, Niwa M, Shigematsu K, Kurihara M, Kataoka Y, Nakao K, Imura H, Matsuo H, Tsuchiyama H, Ozaki M
Department of Pharmacology, Nagasaki University School of Medicine, Japan.
Eur J Pharmacol. 1990 Feb 13;176(3):341-50. doi: 10.1016/0014-2999(90)90028-5.
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.
利用受体放射自显影和膜结合技术，采用[125I]猪脑钠肽-26（BNP-26），对心房钠尿肽家族（ANPs）成员之一的猪脑钠肽-26在肾脏中的特异性结合位点进行了研究。这些结合位点离散地定位于大鼠和猪肾脏中与肾小球和髓质内层在解剖学上相对应的区域。在肾脏中，[125I]BNP-26和[125I]α-大鼠ANP结合位点的定位没有差异。[125I]BNP-26与大鼠肾脏分离的肾小球的溶解膜结合是可饱和的，并且一类高亲和力位点被标记，其解离常数（KD）为372 pM。放射性配体与大鼠髓质内层溶解膜中的两个位点结合，一个低亲和力位点的KD为30 nM，一个高亲和力位点的KD为33 pM。抑制结合的效力顺序为BNP-26 = α-大鼠ANP-(1-28)＞心钠素III（ANP-(103-126)）＞心钠素I（ANP-(103-123)）＞去-Cys105，Cys121-ANP-(104-126)。因此，[125I]BNP-26可能识别肾脏中的ANP受体。必须考虑BNP-26作为一种循环激素通过与ANP受体结合来调节肾脏功能的可能性。
