Evidence for the existence of a sodium-dependent glutathione (GSH) transporter - Expression of bovine brain capillary mRNA and size fractions in Xenopus laevis oocytes and dissociation from gamma-glutamyltranspeptidase and facilitative gsh transporters
Evidence for the existence of a sodium-dependent glutathione (GSH) transporter - Expression of bovine brain capillary mRNA and size fractions in Xenopus laevis oocytes and dissociation from gamma-glutamyltranspeptidase and facilitative gsh transporters
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DOI：
10.1074/jbc.271.16.9754
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发表时间：
1996-04-19
影响因子：
4.8
通讯作者：
Kaplowitz, N
中科院分区：
文献类型：
--
作者：
Kannan, R;Yi, JR;Kaplowitz, N
我们的实验室先前在两种动物模型中显示了明显的载体介导的谷胱甘肽（GSH）穿过血脑屏障（BBB）的摄取。在本研究中，当非洲爪蟾卵母细胞注射完整GSH的牛脑毛细血管mRNA表达时，3天后观察到摄取。当总mRNA转化为cDNA并随后注射到卵母细胞中时，三种不同的组分（5，7-8，和11-12）表达载体介导的完整GSH转运，北方印迹分析确定了RcGshT，先前克隆的钠非依赖性肝小管转运蛋白，仅在级分5中存在，级分7中的GSH转运活性被氯化胆碱替代NaCl和磺溴酞-GSH显著抑制，这两种都不影响RcGshT，Na+依赖性GSH摄取动力学表现出高亲和力（类似于400 μ M）和低亲和力（类似于10 mM）的组件。级分11表达完整GSH的Na+非依赖性转运，并且还含有GGT转录物。总之，我们已经从表达GSH转运的牛脑毛细血管mRNA中鉴定了三种不同大小的转录物：一个馏分表达一种新的Na+-第一次可以明确地与GGT和RcGshT分离，并且可以解释GSH在其电化学梯度下的摄取，的BBB。
Our laboratory previously has shown apparent carrier-mediated glutathione (GSH) uptake across the blood-brain barrier (BBB) in two animal models, In the present study, when Xenopus oocytes were injected with bovine brain capillary mRNA expression of intact GSH, uptake was observed after 3 days, When total mRNA was converted to cDNA and subfractionated with subsequent cRNA injection into oocytes, three distinct fractions (5, 7-8, and 11-12) expressed carrier-mediated intact GSH transport, Northern blot analysis established the presence of RcGshT, the previously cloned sodium-independent hepatic canalicular transporter, only in fraction 5, GSH transport activity in fraction 7 was significantly inhibited by replacement of NaCl with choline chloride and by sulfobromophthalein-GSH, neither of which affects RcGshT, The Na+-dependent GSH uptake kinetics exhibited high affinity (similar to 400 mu M) and low affinity (similar to 10 mM) components. Fraction 11 expressed Na+-independent transport of intact GSH and also contained the GGT transcript, In conclusion, we have identified three distinct sized transcripts from bovine brain capillary mRNA which express GSH transport: one fraction expresses a novel Na+-dependent GSH uptake which can be dissociated unequivocally from both GGT and RcGshT for the first time and which may account for uptake of GSH against its electrochemical gradient at the BBB.