Renal action of atrial natriuretic peptide

通过放射自显影、受体结合研究、清除研究、体外肾小管微灌注等方法研究了心钠素（ANP）与肾脏的相互作用。主要结果如下：（1）放射自显影显示ANP受体分布于肾小球（上皮细胞足突）、血管束和内髓集合管。通过光亲和法标记的ANP受体的溶解，发现肾脏中的受体分子大小为65 kD，而主动脉和肾上腺中含有两种不同分子大小的受体，分别为65 kD和140 kD。(2)用-hANP类似物研究构效关系表明，N端氨基酸、12位氨基酸和环状结构对生理效应是必不可少的。(3)ANP与乙酰胆碱或促胰液素联合肾动脉给药表明，ANP的作用部分由其肾血管作用介导。(4)离体肾小管的体外微灌注未能证明对亨利氏袢和内髓集合管段中的NaCl和水转运有任何影响。(5)ANP的降解，与磷酰胺，是本地化的肾小球和近端小管。

Interactions between atrial natriuretic peptide(ANP) and the kidney were examined by various approaches including autoradiography, receptor binding study, clearance study, in vitro microperfusion of renal tubules, and others. The following 5 major results were obtained: (1) By sutoradiography, we demonstrated that receptors for ANP were distributed in the glomeruli (foot processes of epithelial cells), vascular bundles and inner medullary collecting tubules. By solubilizing ANP-receptors labeled by photoaffinity method, we found that molecular size of the receptors in the kidney is 65 kD wherease the aorta and the adrenal grand contain two kinds of receptors having different molecular size, 65 kD and 140 kD. (2) The structure-activity relationship, examined by using -hANP analogs, showed that amino acids in N-termainus, amino acid at 12th position and ring structure are essential for physiological effects. (3) Intrarenal arterial administration of ANP in combination with acetyl choline or secretin suggested that effects of ANP are mediated in part by its renal vascular action. (4) In vitro microperfusion of isolated renal tubules failed to demonstrate any effects on NaCl and water transport in segments of Henle's loop and inner medullary collecting tubule. (5) Degradation of ANP, inhibitable with phospholamidone, was localized to both the glomeruli and the proximal tubules.