Pathways of glutathione metabolism and transport in isolated proximal tubular cells from rat kidney.
Pathways of glutathione metabolism and transport in isolated proximal tubular cells from rat kidney.
复制标题
DOI：
10.1016/0006-2952(96)00203-1
复制
发表时间：
1996-07
影响因子：
5.8
通讯作者：
Theresa M. Visarius;D. Putt;Joshua M. Schare;D. M. Pegouske;L. Lash
中科院分区：
文献类型：
--
作者：
Theresa M. Visarius;D. Putt;Joshua M. Schare;D. M. Pegouske;L. Lash
在存在和不存在 GSH 周转抑制剂 [阿西维星、L-丁硫氨酸-S、R-亚磺酰亚胺 (BSO)] 的情况下，检查了来自大鼠肾脏的新鲜分离的近端肾小管 (PT) 细胞中外源谷胱甘肽 (GSH) 的细胞摄取和代谢，以量化和评估不同途径在此肾细胞群中处理 GSH 的作用。在阿西维星/BSO 存在下，将 PT 细胞与 2 或 5 mM GSH 一起孵育，10-15 分钟内细胞内 GSH 增加 3 至 4 倍。这些显着较高的细胞内浓度可维持长达 60 分钟。在细胞外 GSH 浓度较低时，观察到细胞内 GSH 浓度最初增加，但这种情况在 60 分钟的时间过程中并未维持。在没有抑制剂的情况下，细胞内 GSH 浓度在前 10-15 分钟内增加至初始值的 2 至 3 倍，但此后降至初始水平以下。在阿西维星/BSO存在和不存在的情况下，PT细胞催化GSH氧化为谷胱甘肽二硫化物(GSSG)以及GSH降解为谷氨酸和半胱氨酸。外源性叔丁基过氧化氢以浓度依赖性方式将细胞内GSH氧化为GSSG，并将细胞外GSSG转运至PT细胞内，但细胞内GSSG还原为GSH的情况有限。此外，细胞与前体氨基酸的孵育几乎不产生GSH的细胞内合成，这表明PT细胞在这些条件下对GSH的生物合成能力有限。因此，GSH 的直接摄取，而不是 GSSG 的还原或前体的再合成，可能是毒理学条件下维持细胞内硫醇氧化还原状态的主要机制。由于 PT 细胞是毒物的主要目标，这些细胞快速吸收和代谢 GSH 的能力可能作为一种防御机制，防止化学损伤。
Cellular uptake and metabolism of exogenous glutathione (GSH) in freshly isolated proximal tubular (PT) cells from rat kidney were examined in the absence and presence of inhibitors of GSH turnover [acivicin, l - buthionine -S ,R-sulfoximine (BSO)] to quantify and assess the role of different pathways in the handling of GSH in this renal cell population. Incubation of PT cells with 2 or 5 mM GSH in the presence of acivicin/BSO produced 3- to 4-fold increases in intracellular GSH within 10–15 min. These significantly higher intracellular concentrations were maintained for up to 60 min. At lower concentrations of extracellular GSH, an initial increase in intracellular GSH concentrations was observed, but this was not maintained for the 60-min time course. In the absence of inhibitors, intracellular concentrations of GSH increased to levels that were 2- to 3-fold higher than initial values in the first 10–15 min, but these dropped below initial levels thereafter. In both the absence and presence of acivicin/BSO, PT cells catalyzed oxidation of GSH to glutathione disulfide (GSSG) and degradation of GSH to glutamate and cyst(e)ine. Exogenous tert-butyl hydroperoxide oxidized intracellular GSH to GSSG in a concentration-dependent manner and extracellular GSSG was transported into PT cells, but limited intracellular reduction of GSSG to GSH occurred. Furthemore, incubation of cells with precursor amino acids produced little intracellular synthesis of GSH, suggesting that PT cells have limited biosynthetic capacity for GSH under these conditions. Hence, direct uptake of GSH, rather than reduction of GSSG or resynthesis from precursors, may be the primary mechanism to maintain intracellular thiol redox status under toxicological conditions. Since PT cells are a primary target for toxicants, the ability of these cells to rapidly take up and metabolize GSH may serve as a defensive mechanism to protect against chemical injury.