Luk J K, Wong E F, Wong N L
Department of Medicine, University of British Columbia University Hospital, Vancouver, Canada.
Nephron. 1994;67(2):226-30. doi: 10.1159/000187933.
The distribution of atrial natriuretic peptide receptor B (ANPR-B) varies between tissues and species. The aim of this study is to determine whether ANPR-B is present in the hamster glomeruli. In vitro C-type natriuretic peptide (CNP)- and atrial natriuretic factor (ANF)-stimulated cGMP accumulation studies were performed in hamster glomeruli. Elevated cGMP accumulations were observed upon ANF addition. No cGMP response was seen with CNP. Competitive receptor-binding experiments were performed with 125I-CNP and 125I-ANF against their respective cold peptides in hamster glomeruli. Although no CNP binding was detected, positive ANF binding was found and two types of ANF receptor were demonstrated. The affinity (Kdl) and maximum binding capacity (Bmaxl) of the high-affinity ANF receptor were 0.014 +/- 0.001 nM and 60.4 +/- 10.2 fmol/mg protein, respectively. Those of the low-affinity receptor (Kd2 and Bmax2) were 45.7 +/- 6.2 nM and 28.3 +/- 6.3 pmol/mg protein, respectively. Similarly, saturation binding experiments also failed to show any CNP receptor binding in hamster glomeruli. This finding suggests that ANPR-B is not present in hamster glomeruli and CNP is not a direct physiological regulator of hamster renal function.
心房利钠肽受体B（ANPR-B）的分布在不同组织和物种之间存在差异。本研究的目的是确定仓鼠肾小球中是否存在ANPR-B。在仓鼠肾小球中进行了体外C型利钠肽（CNP）和心房利钠因子（ANF）刺激的环磷酸鸟苷（cGMP）积累研究。添加ANF后观察到cGMP积累增加。添加CNP未观察到cGMP反应。在仓鼠肾小球中用125I-CNP和125I-ANF与其各自的冷肽进行了竞争性受体结合实验。虽然未检测到CNP结合，但发现了阳性ANF结合，并证实了两种类型的ANF受体。高亲和力ANF受体的亲和力（Kdl）和最大结合容量（Bmaxl）分别为0.014±0.001 nM和60.4±10.2 fmol/mg蛋白质。低亲和力受体（Kd2和Bmax2）的亲和力和最大结合容量分别为45.7±6.2 nM和28.3±6.3 pmol/mg蛋白质。同样，饱和结合实验也未显示仓鼠肾小球中有任何CNP受体结合。这一发现表明仓鼠肾小球中不存在ANPR-B，且CNP不是仓鼠肾功能的直接生理调节因子。
