Production of superoxide through NADH oxidase in thick ascending limb of Henle's loop in rat kidney
Production of superoxide through NADH oxidase in thick ascending limb of Henle's loop in rat kidney
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DOI：
10.1152/ajprenal.00218.2001
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发表时间：
2002-06-01
影响因子：
4.2
通讯作者：
Zou, AP
中科院分区：
文献类型：
--
作者：
Li, N;Yi, FX;Zou, AP
我们最近报道，NADH氧化酶是负责超氧（O（2）（-））的主要酶之一。在大鼠肾脏中产生。然而，NADH氧化酶介导的O（2）（-）的功能意义。生产和调节这种酶活性的机制知之甚少。利用荧光显微成像分析技术，本研究证明，当与二氢乙锭（DHE）孵育时，Henle袢（TALH）的粗升支显示红色荧光，表明O（2）（-）。在这个管状部分中产生。与其他肾单位节段相比，肾皮质和髓质的TALH均显示出最高的荧光强度。通过将皮质TALHS（cTALHS）与NADH氧化酶、黄嘌呤氧化酶、一氧化氮合酶、花生四烯酸代谢酶和线粒体内氧化酶的底物一起孵育，发现NADH氧化酶是O（2）（-）最重要的酶之一。在这段管道中生产。NADH氧化酶抑制剂diphenyleneiodonium（DPI; 100 μ M）完全阻断NADH诱导的O（2）（-）。cTALH的生产。将cTALHs暴露于低PO（2）（5-10 Torr）显著增加O（2）（-）。无论是否存在NADH。此外，血管紧张素II（100 nM）增加NADH氧化酶活性的32%，这是完全阻断DPI。这些结果表明，NADH氧化酶是O（2）（-）的主要酶。TALHs的产生和O（2）（-）的产生。可能通过肾组织氧合和循环激素调节。
We recently reported that NADH oxidase is one of the major enzymes responsible for superoxide (O(2)(-).) production in the rat kidney. However, the functional significance of NADH oxidase-mediated O(2)(-). production and the mechanisms regulating this enzyme activity are poorly understood. Using fluorescence microscopic imaging analysis, the present study demonstrated that thick ascending limbs of Henle's loop (TALHs) exhibited red fluorescence when incubated with dihydroethidium (DHE), suggesting that O(2)(-). is produced in this tubular segment. Compared with other nephron segments, TALHs from both renal cortex and medulla showed the highest fluorescence intensity. By incubating cortical TALHs (cTALHs) with the substrates of NADH oxidase, xanthine oxidase, nitric oxide synthase, arachidonic acid-metabolizing enzymes, and intramitochondrial oxidases, NADH oxidase was found to be one of the most important enzymes for O(2)(-). production in this tubular segment. The NADH oxidase inhibitor diphenyleneiodonium (DPI; 100 muM) completely blocked NADH-induced O(2)(-). production in cTALHs. Exposure of cTALHs to low PO(2) (5-10 Torr) significantly increased O(2)(-). production regardless of the absence or presence of NADH. Furthermore, angiotensin II (100 nM) increased NADH oxidase activity by 32%, which was completely blocked by DPI. These results suggest that NADH oxidase is a major enzyme responsible for O(2)(-). production in the TALHs and that the production of O(2)(-). via NADH oxidase may be regulated by renal tissue oxygenation and circulating hormones.