Olson L J, Lowe D G, Drewett J G
Department of Pharmacology and Toxicology, Medical College of Wisconsin, Milwaukee 53226, USA.
Mol Pharmacol. 1996 Aug;50(2):430-5.
We report the production of a novel human natriuretic peptide receptor/guanylyl cyclase A (hNPR-A)-selective agonist ANP [G9T, R11S, G16R] (sANP). This agonist has similar affinity to ANP for hNPR-A and 1,000-10,000-fold reduced affinity for the human natriuretic peptide clearance receptor (hNPR-C). sANP was used to directly test the hypothesis that hNPR-A mediates the inhibitory effect of natriuretic peptides on aldosterone generation in a human zona glomerulosa cell line, H295R. Human type A natriuretic peptide and sANP (10(-11) to 10(-6) M) resulted in concentration-dependent increases in cGMP levels and decreases in forskolin (100 nM)- and angiotensin II (5 nM)-induced aldosterone and pregnenolone production. These results revealed an inhibitory effect of both peptides on the agonist-stimulated conversion of cholesterol to pregnenolone (i.e., cytochrome P-450 cholesterol monooxygenase side-chain cleaving enzyme, EC 1.14.15.6). H295R cells also exhibited angiotensin II- and forskolin-evoked conversion of [3H]cortico-sterone to [3H]aldosterone (i.e., cytochrome P-450 steroid 11 beta-monooxygenase/aldosterone synthase, EC 1.14.15.4). Human type A natriuretic peptide and sANP (10(-7) M) inhibited the angiotensin II-stimulated late pathway but did not affect forskolin-facilitated conversion of corticosterone to aldosterone. Our results directly demonstrate inhibitory effects of hNPR-A-mediated signal transduction on cytochrome P-450 cholesterol monooxygenase side-chain cleaving enzyme and steroid 11 beta-monooxygenase/aldosterone synthase complex depending on the steroidogenic agonist used.
我们报告了一种新型人利钠肽受体/鸟苷酸环化酶A（hNPR-A）选择性激动剂ANP [G9T，R11S，G16R]（sANP）的产生。该激动剂对hNPR-A的亲和力与ANP相似，而对人利钠肽清除受体（hNPR-C）的亲和力降低了1000至10000倍。sANP被用于直接验证以下假设：hNPR-A介导利钠肽对人球状带细胞系H295R中醛固酮生成的抑制作用。人A型利钠肽和sANP（10^-11至10^-6 M）导致cGMP水平呈浓度依赖性升高，以及福斯可林（100 nM）和血管紧张素II（5 nM）诱导的醛固酮和孕烯醇酮生成减少。这些结果揭示了两种肽对激动剂刺激的胆固醇向孕烯醇酮转化（即细胞色素P-450胆固醇单加氧酶侧链裂解酶，EC 1.14.15.6）均有抑制作用。H295R细胞还表现出血管紧张素II和福斯可林诱发的[3H]皮质酮向[3H]醛固酮的转化（即细胞色素P-450类固醇11β-单加氧酶/醛固酮合酶，EC 1.14.15.4）。人A型利钠肽和sANP（10^-7 M）抑制了血管紧张素II刺激的晚期途径，但不影响福斯可林促进的皮质酮向醛固酮的转化。我们的结果直接证明了hNPR-A介导的信号转导对细胞色素P-450胆固醇单加氧酶侧链裂解酶和类固醇11β-单加氧酶/醛固酮合酶复合物的抑制作用，这取决于所使用的类固醇生成激动剂。
