Mak I T, Komarov A M, Wagner T L, Stafford R E, Dickens B F, Weglicki W B
Department of Medicine, George Washington University Medical Center, Washington, District of Columbia 20037, USA.
Am J Physiol. 1996 Jul;271(1 Pt 1):C385-90. doi: 10.1152/ajpcell.1996.271.1.C385.
The effect of dietary Mg deficiency on nitric oxide (NO) production and its role in mediating oxidative depletion of red blood cell (RBC) glutathione in rats were investigated. Male Sprague-Dawley rats were placed on Mg-deficient or Mg-sufficient diets for up to 3 wk. Plasma nitrate plus nitrite levels, determined by the Escherichia coli reductase/Griess reagent procedures, increased 1.7-fold during the 1st wk and increased 2- to 2.4-fold during the 2nd and 3rd wk on the Mg-deficient diet. In association, substantial losses (approximately 50%) of RBC glutathione occurred during the 2nd and 3rd wk. Administration of the NO synthesis inhibitor NG-nitro-L-arginine methyl ester (L-NAME) in drinking water (0.5 mg/ml) effectively blunted the increases in plasma nitrate/nitrite during Mg deficiency. Concomitantly, losses of RBC glutathione exhibited by Mg-deficient rats were significantly attenuated. Packed RBCs, obtained from Mg-deficient but not from Mg-sufficient animals, displayed a prominent nitrosyl hemoglobin signal detected by electron spin resonance spectroscopy; the signals of the samples from the L-NAME-treated Mg-deficient rats were greatly reduced. With isolated RBCs, losses of the glutathione could be induced directly by peroxynitrite or 3-morpholinosydnonimine, which generates NO + .O2-, but not by NO (from sodium nitroprusside) alone, in a concentration-dependent manner. The results clearly indicate that NO overproduction occurs and participates in RBC glutathione loss during Mg deficiency. Because neutrophil activation also occurs, we suggest that NO might interact with superoxide anions to form peroxynitrite, which then directly oxidizes RBC glutathione.
研究了膳食镁缺乏对大鼠一氧化氮（NO）生成的影响及其在介导红细胞（RBC）谷胱甘肽氧化消耗中的作用。将雄性Sprague-Dawley大鼠置于缺镁或镁充足的饮食中长达3周。通过大肠杆菌还原酶/格里斯试剂法测定的血浆硝酸盐加亚硝酸盐水平，在缺镁饮食的第1周增加了1.7倍，在第2周和第3周增加了2至2.4倍。与此同时，在第2周和第3周红细胞谷胱甘肽大量损失（约50%）。在饮用水中给予NO合成抑制剂NG-硝基-L-精氨酸甲酯（L-NAME，0.5 mg/ml）可有效抑制缺镁期间血浆硝酸盐/亚硝酸盐的增加。同时，缺镁大鼠红细胞谷胱甘肽的损失明显减轻。从缺镁但非镁充足的动物获得的压积红细胞，通过电子自旋共振光谱检测显示出明显的亚硝基血红蛋白信号；L-NAME处理的缺镁大鼠样本的信号大大降低。对于分离的红细胞，谷胱甘肽的损失可由过氧亚硝酸盐或3-吗啉代-sydnonimine直接诱导，后者产生NO +.O2-，但单独的NO（来自硝普钠）则不能以浓度依赖的方式诱导。结果清楚地表明，在镁缺乏期间会发生NO过量生成并参与红细胞谷胱甘肽的损失。由于中性粒细胞激活也会发生，我们认为NO可能与超氧阴离子相互作用形成过氧亚硝酸盐，然后过氧亚硝酸盐直接氧化红细胞谷胱甘肽。
