Tissue-specific changes in glutathione and cysteine after buthionine sulfoximine treatment of rats and the potential for artifacts in thiol levels resulting from tissue preparation.
Tissue-specific changes in glutathione and cysteine after buthionine sulfoximine treatment of rats and the potential for artifacts in thiol levels resulting from tissue preparation.
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DOI：
10.1016/0041-008x(91)90208-v
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发表时间：
1991-02
影响因子：
3.8
通讯作者：
A. Standeven;K. Wetterhahn
中科院分区：
文献类型：
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作者：
A. Standeven;K. Wetterhahn
L-丁硫氨酸-S，R-亚磺胺，是一种有效的γ-谷氨酰半胱氨酸合成酶抑制剂，常被用作谷胱甘肽特异性耗竭的实验工具。由于半胱氨酸是谷胱甘肽生物合成的关键前体，我们研究了BSO在体内也可能影响大鼠肝和肾组织中游离半胱氨酸库的可能性。雄性Cd(SD)BR大鼠(15 0~2 0 0g)ip不同剂量的硫代巴比妥钠(0.2 5−4.0 m ol/kg)，用高效液相色谱结合电化学检测和/或光谱技术测定肝、肾组织中谷胱甘肽和半胱氨酸的含量。BSO最大剂量(4.0 mm o l/kg)未见肝肾毒性。BSO在所有剂量下均引起肝脏和肾脏谷胱甘肽的预期下降，尽管谷胱甘肽的耗竭更快，在更低的BSO剂量下实现，并且在肾脏中比在肝脏中更持久。BSO(1.0 mmol/kg，ip)处理20min后，肝脏半胱氨酸水平几乎增加一倍，但在随后的时间点与对照组无显著差异。相反，肾脏半胱氨酸在注射后20分钟至25小时内显著耗尽，其时间进程与肾脏谷胱甘肽耗竭的时间进程密切相关。这些变化在谷胱甘肽和半胱氨酸的器官间和器官内转运模型的背景下进行了讨论。我们还提供了证据表明，一种人工制品，最有可能是γ-谷氨酰转肽酶(GGT)启动的谷胱甘肽的分解，导致死后大鼠肝脏特别是肾脏中半胱氨酸水平的快速增加。肾脏中的GSH水平同时降低。在肾脏和其他富含GGT的器官中的谷胱甘肽和半胱氨酸的毒理学研究中，需要尽量减少这种伪影，因为这些硫醇的测量水平可能不能反映体内发生的真实浓度。
l-Buthionine-S,R-sulfoximine (BSO), a potent inhibitor of γ-glutamylcysteine synthetase, is commonly used as an experimental tool for the specific depletion of glutathione. Since cysteine is a key precursor for glutathione biosynthesis, we investigated the possibility that BSO might also affect the free cysteine pool in rat liver and kidney tissues in vivo. Male CD(SD)BR rats (150–200 g) were injected ip with various doses of BSO (0.25−4.0 mmol/kg), and glutathione and cysteine were measured in liver and kidney using HPLC with electrochemical detection and/or spectroscopic techniques. No hepatotoxicity or nephrotoxicity was observed at the highest BSO dose (4.0 mmol/kg) used. BSO caused the expected decreases of hepatic and renal glutathione at all doses, although glutathione depletion was more rapid, was achieved at a lower BSO dose, and was more sustained in kidney than in liver. Hepatic cysteine levels nearly doubled 20 min after BSO treatment (1.0 mmol/kg, ip), but were not significantly different from control at later time points. In contrast, renal cysteine was significantly depleted from 20 min to 25 hr postinjection with a time course closely paralleling that of renal glutathione depletion. These changes are discussed in the context of models for inter- and intraorgan transport of glutathione and cysteine. We also provide evidence that an artifact, most likely the γ-glutamyltranspeptidase (GGT)-initiated breakdown of glutathione, leads to a rapid postmortem increase of cysteine levels in liver and particularly in kidney of rats. Simultaneous decreases in GSH levels can be demonstrated in kidney. This artifact needs to be minimized in toxicological studies of glutathione and cysteine in kidney and other GGT-rich organs, as the measured levels of these thiols may not reflect the true concentrations occurring in vivo.