Kowalski D P, Feeley R M, Jones D P
Department of Biochemistry, Emory University, Atlanta, GA 30322.
J Nutr. 1990 Sep;120(9):1115-21. doi: 10.1093/jn/120.9.1115.
The potential effects of dietary glutathione on the metabolism of peroxidized lipid ingested in the diet were studied using everted sacs of rat small intestine and peroxidized methyl linoleate. Peroxidized methyl linoleate was added to the luminal side, and the appearance of thiobarbituric acid-reactive (TBA-reactive) material on the contraluminal side was measured. Incubation with N,N,bis(2-chloroethyl)-N-nitrosourea (BCNU) under conditions in which it inhibits the glutathione disulfide reductase/glutathione peroxidase system increased the appearance of TBA-reactive material, indicating that at least a portion of the TBA-reactive material passing through the epithelium is peroxide in nature. Adding glutathione (GSH) to the luminal side substantially decreased the appearance of TBA-reactive material on the contraluminal side, either without or with BCNU treatment. Inhibition of GSH transport and control experiments with GSH, peroxidized methyl linoleate and purified brush border membranes showed that this decrease was due primarily to uptake of luminal GSH and its use to support intracellular GSH-dependent reactions. Thus, the results indicate that exogenous GSH, which can exist in certain diets, can be taken up by the small intestine and used to protect against absorption of lipid peroxidation products.
利用大鼠小肠外翻囊和过氧化亚油酸甲酯，研究了膳食谷胱甘肽对膳食中摄入的过氧化脂质代谢的潜在影响。将过氧化亚油酸甲酯添加到腔侧，并测量对侧硫代巴比妥酸反应性（TBA反应性）物质的出现情况。在抑制谷胱甘肽二硫化物还原酶/谷胱甘肽过氧化物酶系统的条件下，用N，N-双（2-氯乙基）-N-亚硝基脲（BCNU）孵育会增加TBA反应性物质的出现，这表明至少一部分穿过上皮的TBA反应性物质本质上是过氧化物。在无BCNU处理或有BCNU处理的情况下，向腔侧添加谷胱甘肽（GSH）都会显著减少对侧TBA反应性物质的出现。对GSH转运的抑制以及用GSH、过氧化亚油酸甲酯和纯化的刷状缘膜进行的对照实验表明，这种减少主要是由于腔侧GSH的摄取及其用于支持细胞内依赖GSH的反应。因此，结果表明，某些饮食中存在的外源性GSH可被小肠吸收，并用于防止脂质过氧化产物的吸收。
