Eberle D, Clarke R, Kaplowitz N
J Biol Chem. 1981 Mar 10;256(5):2115-7.
Biliary excretion of glutathione has recently been described but poorly characterized. Controversy has existed concerning the relative contribution of oxidized and reduced glutathione to total glutathione efflux from the liver into bile. We found that bile, unlike liver cytosol or buffer, had the unique ability to oxidize GSH rapidly (t 1/2 = 5 min) to the disulfide form by a nonenzymatic, O2, and pH-dependent chemical reaction inhibited by only certain chelating agents. Significant oxidation of GSH occurred during the collection of bile samples resulting in significant time-dependent alterations in the ratio of biliary GSH to GSSG. Thus the preponderance of GSSG in bile in the normal state reported by others represents a postexcretory in vitro artifact. Inhibition of oxidation by acidification of bile during its collection established the true contribution of GSH and GSSG to total biliary efflux.
谷胱甘肽的胆汁排泄最近已有报道，但对其特征的描述较少。关于氧化型谷胱甘肽和还原型谷胱甘肽对肝脏向胆汁中总谷胱甘肽流出的相对贡献一直存在争议。我们发现，与肝细胞溶质或缓冲液不同，胆汁具有独特的能力，能通过一种仅受某些螯合剂抑制的非酶促、依赖氧气和pH的化学反应，迅速（t1/2 = 5分钟）将谷胱甘肽氧化为二硫键形式。在胆汁样本采集过程中，谷胱甘肽发生了显著氧化，导致胆汁中谷胱甘肽与氧化型谷胱甘肽的比例出现显著的时间依赖性变化。因此，其他人报道的正常状态下胆汁中氧化型谷胱甘肽占优势代表了一种排泄后的体外假象。在胆汁采集过程中通过酸化胆汁来抑制氧化，确定了谷胱甘肽和氧化型谷胱甘肽对总胆汁流出的真正贡献。
