Hama N, Itoh H, Suga S, Komatsu Y, Yoshimasa T, Nakao K
Department of Medicine, Kyoto University School of Medicine, Japan.
J Endocrinol. 1994 Jun;141(3):473-9. doi: 10.1677/joe.0.1410473.
C-type natriuretic peptide (CNP), the third member of natriuretic peptides, has recently been discovered from the porcine brain. Using a polyclonal antiserum to CNP, we demonstrated that CNP-like immunoreactivity (CNP-LI) is present mainly in the central nervous system. Recently, however, we have discovered the production and secretion of CNP in vascular endothelial cells. These observations suggested that CNP may act not only as a neuropeptide but also as a local regulator of vascular tone or growth. In order to further clarify the pathophysiological significance of CNP, we aimed at the preparation of a monoclonal antibody to CNP. A monoclonal antibody to CNP, KY-CNP-I, has been produced. This monoclonal antibody belongs to the immunoglobulin G1 subclass and has high affinity for CNP. Using this monoclonal antibody, we established a specific radioimmunoassay (RIA) for CNP. The RIA detected CNP-LI in rat brain extracts and culture media conditioned with bovine endothelial cells. In addition, the pretreatment of cultured aortic smooth muscle cells with KY-CNP-I attenuated cyclic GMP production induced by CNP in vitro. The preadministration of KY-CNP-I to rats also attenuated plasma cyclic GMP increase after intravenous injection of CNP in vivo. These results indicate that this monoclonal antibody is a useful tool to clarify the pathophysiological role of CNP as a neuropeptide and as a local vascular regulator.
C型利钠肽（CNP）是利钠肽家族的第三个成员，最近从猪脑中被发现。我们使用针对CNP的多克隆抗血清，证明了CNP样免疫反应性（CNP-LI）主要存在于中枢神经系统中。然而，最近我们发现血管内皮细胞能够产生和分泌CNP。这些观察结果表明，CNP可能不仅作为一种神经肽发挥作用，还作为血管张力或生长的局部调节因子。为了进一步阐明CNP的病理生理意义，我们旨在制备一种针对CNP的单克隆抗体。现已制备出一种针对CNP的单克隆抗体KY-CNP-I。这种单克隆抗体属于免疫球蛋白G1亚类，对CNP具有高亲和力。利用这种单克隆抗体，我们建立了一种针对CNP的特异性放射免疫测定法（RIA）。该RIA可检测大鼠脑提取物和牛内皮细胞条件培养基中的CNP-LI。此外，用KY-CNP-I对培养的主动脉平滑肌细胞进行预处理，可减弱体外CNP诱导的环磷酸鸟苷（cGMP）生成。在体内给大鼠预先注射KY-CNP-I，也可减弱静脉注射CNP后血浆cGMP的升高。这些结果表明，这种单克隆抗体是阐明CNP作为神经肽和局部血管调节因子的病理生理作用的有用工具。
