Vos O, Roos-Verhey W S
TNO, Medical Biological Laboratory, Rijswijk, The Netherlands.
Int J Radiat Biol Relat Stud Phys Chem Med. 1988 Feb;53(2):273-81. doi: 10.1080/09553008814550621.
Monoethyl (MEE) and diethyl (DEE) esters of glutathione (GSH) had the capacity to provide some protection of normal and buthionine sulfoximine (BSO) pretreated cells against X-irradiation. Both compounds appeared to be transported through the cell membrane into the cells. MEE was intracellularly partly hydrolysed to GSH and caused a limited rise of intracellular GSH. DEE was intracellularly mainly converted into MEE and partly into GSH. DEE caused a larger rise of the intracellular GSH content than MEE; it also provided a better radioprotection. Radioprotection by the GSH esters may be explained by an increase of intracellular GSH as well as by the presence of the esters themselves. Cysteamine caused no rise of the intracellular GSH content, thus its radioprotection could not be mediated by an increase of intracellular GSH. When the radiosensitivity of GSH-depleted cells protected by cysteamine was compared with the radiosensitivity of non-GSH-depleted cells similarly protected by cysteamine, it appeared that the GSH-depleted cells remained more sensitive to irradiation. Thus, it seems that in this respect cysteamine cannot fully substitute for endogenous GSH.
谷胱甘肽（GSH）的单乙酯（MEE）和二乙酯（DEE）能够为正常细胞和经丁硫氨酸亚砜亚胺（BSO）预处理的细胞提供一定程度的抗X射线辐射保护。这两种化合物似乎都能通过细胞膜转运进入细胞。MEE在细胞内部分水解为GSH，导致细胞内GSH含量有限升高。DEE在细胞内主要转化为MEE，部分转化为GSH。DEE使细胞内GSH含量升高幅度大于MEE；它还提供了更好的辐射防护。GSH酯的辐射防护作用可能是由于细胞内GSH增加以及酯本身的存在。半胱胺不会导致细胞内GSH含量升高，因此其辐射防护作用不能通过细胞内GSH增加来介导。当比较经半胱胺保护的GSH耗竭细胞的辐射敏感性与同样经半胱胺保护的非GSH耗竭细胞的辐射敏感性时，发现GSH耗竭细胞对辐射仍更敏感。因此，在这方面半胱胺似乎不能完全替代内源性GSH。
