Umeki S, Soejima R
Department of Medicine, Kawasaki Medical School, Okayama, Japan.
Biochim Biophys Acta. 1990 Apr 9;1052(1):211-5. doi: 10.1016/0167-4889(90)90078-r.
The effects of hydrocortisone on the respiratory burst oxidase (NADPH oxidase, EC 1.6.99.6) from human neutrophils in both whole-cell and full soluble (cell-free) systems were investigated. In the whole-cell system, hydrocortisone inhibited the generation of superoxide by neutrophils exposed to phorbol myristate acetate, suggesting that steroids inhibit the bactericidal capacity of the body in an acute inflammatory phase. Hydrocortisone, which was added to the cuvette after the addition of NADPH and before the addition of sodium dodecyl sulfate, in a cell-free system, was found to inhibit the activation of superoxide-generating NADPH oxidase by sodium dodecyl sulfate. The concentration of hydrocortisone required for 50% inhibition of oxidase was 40 microM. Its inhibition was dose- and time-dependent in the cell-free system. However, hydrocortisone did not alter the Km of the oxidase for NADPH. These results suggest that steroids inhibit the reconstitution of NADPH oxidase by sodium dodecyl sulfate in the cell-free system, and that they do not alter the affinity to NADPH of the oxidase.
研究了氢化可的松在全细胞和完全可溶（无细胞）系统中对人中性粒细胞呼吸爆发氧化酶（NADPH氧化酶，EC 1.6.99.6）的影响。在全细胞系统中，氢化可的松抑制了暴露于佛波酯肉豆蔻酸酯的中性粒细胞中超氧化物的生成，这表明类固醇在急性炎症期抑制了机体的杀菌能力。在无细胞系统中，在加入NADPH后且在加入十二烷基硫酸钠之前将氢化可的松加入比色皿中，发现其可抑制十二烷基硫酸钠对产生超氧化物的NADPH氧化酶的激活。抑制氧化酶活性50%所需的氢化可的松浓度为40微摩尔。在无细胞系统中，其抑制作用呈剂量和时间依赖性。然而，氢化可的松并未改变氧化酶对NADPH的米氏常数。这些结果表明，类固醇在无细胞系统中抑制十二烷基硫酸钠对NADPH氧化酶的重组，且它们不会改变氧化酶对NADPH的亲和力。
