Kang D G, Kim J W, Lee J
Department of Physiology, Chonnam University Medical School, 5 Hak-dong, Kwangju, 501-190, Korea.
Pharmacol Res. 2000 Jan;41(1):123-7. doi: 10.1006/phrs.1999.0570.
The present study was aimed at investigating the role of endogenous nitric oxide (NO) in regulating Na,K-ATPase activity in the kidney. The expression of alpha-1 and beta-1 subunits; and the enzymatic activity of Na,K-ATPase were determined in the kidney of rats treated with an NO synthase inhibitor, N(G)-nitro-L-arginine methyl ester (L-NAME). Following the treatment with L-NAME in the drinking water for 4 weeks, Na,K-ATPase activity was increased while tissue nitrite/nitrate levels were decreased in the kidney. Supplementation with L-arginine prevented the L-NAME-induced changes. The expression of either alpha-1 or beta-1 subunit protein of Na,K-ATPase, assessed by Western blot analysis, was not affected by L-NAME-treatment. An acute in vitro treatment of the kidney with L-NAME also caused an increase of Na,K-ATPase activity; which was again prevented by cotreatment with L-arginine. On the contrary, treatment with sodium nitroprusside significantly decreased Na,K-ATPase activity. These results suggest that the endogenous NO plays a direct inhibitory role on Na,K-ATPase activity in the kidney.
本研究旨在探讨内源性一氧化氮（NO）在调节肾脏中钠钾ATP酶活性方面的作用。在给予一氧化氮合酶抑制剂N(G)-硝基-L-精氨酸甲酯（L-NAME）处理的大鼠肾脏中，测定了α-1和β-1亚基的表达以及钠钾ATP酶的酶活性。在用L-NAME处理饮用水4周后，肾脏中的钠钾ATP酶活性增加，而组织中亚硝酸盐/硝酸盐水平降低。补充L-精氨酸可防止L-NAME诱导的变化。通过蛋白质印迹分析评估，L-NAME处理对钠钾ATP酶α-1或β-1亚基蛋白的表达没有影响。用L-NAME对肾脏进行急性体外处理也会导致钠钾ATP酶活性增加；用L-精氨酸共同处理可再次阻止这种增加。相反，硝普钠处理可显著降低钠钾ATP酶活性。这些结果表明，内源性NO对肾脏中的钠钾ATP酶活性起直接抑制作用。
