Noguchi K, Hattori T, Igarashi T, Ueno K, Satoh T, Kitagawa H, Hori H, Shibata T, Inayama S
Life Sci. 1985 Aug 19;37(7):625-33. doi: 10.1016/0024-3205(85)90429-1.
A comparative study of the effect of misonidazole and novel radiosensitizers on glutathione (GSH) levels and related enzyme activities in isolated rat hepatocytes was performed. Incubation of hepatocytes with 5 mM radiosensitizers led to a decrease in the intracellular GSH level. The most pronounced decrease in cellular GSH was evoked by 2,4-dinitroimidazole-1-ethanol (DNIE); after incubation for only 15 min, GSH was hardly detected. DNIE-mediated GSH loss was dependent upon its concentration. DNIE reacted with GSH nonenzymatically as well as with diethylmaleate, while misonidazole and 1-methyl-2-methyl-sulfinyl-5-methoxycarbonylimidazole (KIH-3) did not. Addition of partially purified glutathione S-transferase (GST) did not enhance DNIE-mediated GSH loss in a cell-free system. DNIE inhibited glutathione peroxidase (GSH-Px), GST, and glutathione reductase (GSSG-R) activities in hepatocytes, while misonidazole and KIH-3 did not. GSH-Px activity assayed with H2O2 as substrate was the most inhibited. Inhibition of GSH-Px activity assayed with cumene hydroperoxide as substrate and GST was less than that of GSH-Px assayed with H2O2 as substrate. GSSG-R activity was decreased by DNIE, but not significantly. Incubation of purified GSH-Px with DNIE resulted in a little change in the activity when assayed with H2O2 as substrate.
进行了一项关于米索硝唑和新型放射增敏剂对离体大鼠肝细胞中谷胱甘肽（GSH）水平及相关酶活性影响的比较研究。用5 mM放射增敏剂孵育肝细胞会导致细胞内GSH水平降低。2,4-二硝基咪唑-1-乙醇（DNIE）引起的细胞内GSH下降最为明显；仅孵育15分钟后，几乎检测不到GSH。DNIE介导的GSH损失取决于其浓度。DNIE与GSH发生非酶反应，也与马来酸二乙酯反应，而米索硝唑和1-甲基-2-甲基亚磺酰基-5-甲氧基羰基咪唑（KIH-3）则不会。在无细胞体系中添加部分纯化的谷胱甘肽S-转移酶（GST）并不会增强DNIE介导的GSH损失。DNIE抑制肝细胞中的谷胱甘肽过氧化物酶（GSH-Px）、GST和谷胱甘肽还原酶（GSSG-R）活性，而米索硝唑和KIH-3则不会。以H2O2为底物测定的GSH-Px活性受到的抑制最为显著。以氢过氧化异丙苯为底物测定的GSH-Px活性和GST受到的抑制小于以H2O2为底物测定的GSH-Px。DNIE使GSSG-R活性降低，但不显著。用DNIE孵育纯化的GSH-Px，以H2O2为底物测定时，活性略有变化。
