Kim Soo Mi, Kim Yoon Ah, Kim Sun Young, Kim Suhn Hee, Cho Kyung Woo, Kim Sung Zoo
Department of Physiology, Institute for Medical Sciences, Center for Healthcare Technology Development, Chonbuk National University Medical School, Jeonju 561-180, Republic of Korea.
Regul Pept. 2011 Feb 25;167(1):42-9. doi: 10.1016/j.regpep.2010.11.010. Epub 2010 Dec 2.
Natriuretic peptides help to maintain sodium and fluid volume homeostasis in a healthy cardio-renal environment. Since the identification of Dendroaspis natriuretic peptide (DNP) as a new member of the natriuretic peptide family, DNP has been considered as an important regulator of natriuresis and dieresis. The present study was undertaken to investigate the presence of immunoreactive Dendroaspis natriuretic peptide (DNP) and its specific receptor in rabbit. DNP was detected in heart, kidney, liver, brain, and plasma by radioimmunoassay (RIA). DNP contents of cardiac atrium and ventricle, renal cortex and medulla, liver, and brain were 1.42 ± 0.15, 1.0 6 ± 0.08, 2.55 ± 0.21, 1.81 ± 0.16, 1.36 ± 0.22, and 0.69 ± 0.15 pg/mg of wet weight, respectively. The concentration of DNP in plasma was 235.44 ± 15.44 pg/ml. By quantitative in vitro receptor autoradiography, specific ¹²⁵I-DNP binding sites were revealed in glomeruli, interlobular artery, acuate artery, vasa recta bundle, and inner medulla of the kidney with an apparent dissociation constant (K(d)) of 0.29 ± 0.05, 0.36 ± 0.03, 0.84 ± 0.19, 1.18 ± 0.23, and 10.91 ± 1.59 nM, respectively. Basal rate of 3', 5'-cyclic guanosine monophosphate (cGMP) production by particulate guanylyl cyclase (GC) activation of glomerular membranes was basally 13.40 ± 1.70 pmol/mg protein/min. DNP caused an increment of cGMP production in similar magnitude to that caused by ANP, BNP, and urodilatin, while the production of cGMP by CNP was significantly lower than that by DNP. Our results show that plasma levels of DNP were higher when compared to other tissues. DNP produces cGMP via the NPR-A receptor subtype in the kidney, similarly to ANP and BNP, suggesting that plasma DNP could have similar functions as ANP and BNP.
利钠肽有助于在健康的心肾环境中维持钠和液体容量的稳态。自从树眼镜蛇利钠肽（DNP）被鉴定为利钠肽家族的新成员以来，DNP就被认为是利钠和利尿的重要调节因子。本研究旨在调查兔体内免疫反应性树眼镜蛇利钠肽（DNP）及其特异性受体的存在情况。通过放射免疫分析（RIA）在心脏、肾脏、肝脏、大脑和血浆中检测到了DNP。心房、心室、肾皮质和髓质、肝脏以及大脑中DNP的含量分别为1.42±0.15、1.06±0.08、2.55±0.21、1.81±0.16、1.36±0.22和0.69±0.15 pg/mg湿重。血浆中DNP的浓度为235.44±15.44 pg/ml。通过定量体外受体放射自显影，在肾小球、小叶间动脉、弓形动脉、直小血管束和肾内髓质中发现了特异性的¹²⁵I-DNP结合位点，其表观解离常数（K(d)）分别为0.29±0.05、0.36±0.03、0.84±0.19、1.18±0.23和10.91±1.59 nM。肾小球膜颗粒型鸟苷酸环化酶（GC）激活产生3',5'-环鸟苷单磷酸（cGMP）的基础速率为13.40±1.70 pmol/mg蛋白质/分钟。DNP引起的cGMP产生增加幅度与心房钠尿肽（ANP）、脑钠肽（BNP）和尿舒张素引起的相似，而C型钠尿肽（CNP）引起的cGMP产生明显低于DNP。我们的结果表明，与其他组织相比，血浆中DNP的水平更高。DNP与ANP和BNP类似，通过肾脏中的NPR-A受体亚型产生cGMP，这表明血浆DNP可能具有与ANP和BNP相似的功能。
