Ozaki M, Aoki S, Masuda Y
Division of Toxicology, Niigata College of Pharmacy, Japan.
Jpn J Pharmacol. 1994 Jul;65(3):183-91. doi: 10.1254/jjp.65.183.
The tert-butyl hydroperoxide (BHP)-induced release of oxidized glutathione (GSSG) and K+ was studied in relation to lipid peroxidation and cell death using isolated perfused rat livers. Infusion of BHP into the perfused liver resulted in an early and simultaneous release of GSSG and K+ and a sustained release of thiobarbituric-acid-reactive substances (TBARS) into the effluent perfusate, which was followed by further prenecrotic leakage of K+ followed by lactic dehydrogenase (LDH). These actions of BHP were not significantly affected by cutting or ligating the bile duct, and they were potentiated by omitting Ca2+ from the perfusion medium. Co-infusion of desferrioxamine, propyl gallate and diethyldithiocarbamate suppressed TBARS release as well as the later leakage of K+ and LDH. Desferrioxamine was also effective under Ca(2+)-free conditions. N,N'-diphenyl-p-phenylenediamine inhibited TBARS release, but it was not protective against cell death, although there was some delay. The action of dithiothreitol was only moderate. On the other hand, leakage of TBARS, K+ (prenecrotic) and LDH was enhanced by cysteamine and beta-mercaptoethanol and most markedly enhanced by ferrous iron. However, none of these agents markedly affected the early release of GSSG and K+. These observations, which support our previous findings, suggest that the early and coupled sinusoidal efflux of GSSG and K+ caused by BHP is independent of lipid peroxidation and cell death and that they represent a physiological mechanism of GSSG release. The results also suggest that lipid peroxidation is not the sole cause of BHP-induced cell death.
使用离体灌注大鼠肝脏，研究了叔丁基过氧化氢（BHP）诱导的氧化型谷胱甘肽（GSSG）和钾离子（K⁺）释放与脂质过氧化和细胞死亡的关系。向灌注肝脏中输注BHP导致GSSG和K⁺早期同时释放，以及硫代巴比妥酸反应性物质（TBARS）持续释放到流出的灌注液中，随后K⁺进一步在坏死前泄漏，接着是乳酸脱氢酶（LDH）泄漏。BHP的这些作用不受切断或结扎胆管的显著影响，并且通过从灌注培养基中省略钙离子（Ca²⁺）而增强。去铁胺、没食子酸丙酯和二乙基二硫代氨基甲酸盐共同输注可抑制TBARS释放以及随后K⁺和LDH的泄漏。去铁胺在无Ca²⁺条件下也有效。N，N'-二苯基对苯二胺抑制TBARS释放，但尽管有一定延迟，它对细胞死亡没有保护作用。二硫苏糖醇的作用仅为中等程度。另一方面，半胱胺和β-巯基乙醇增强了TBARS、K⁺（坏死前）和LDH的泄漏，而亚铁离子最显著地增强了这种泄漏。然而，这些试剂均未显著影响GSSG和K⁺的早期释放。这些观察结果支持了我们之前的发现，表明BHP引起的GSSG和K⁺早期耦合性窦状隙外流独立于脂质过氧化和细胞死亡，并且它们代表了GSSG释放的一种生理机制。结果还表明脂质过氧化不是BHP诱导细胞死亡的唯一原因。
