Glucose transport in isolated brush border membrane from rat small intestine.
Glucose transport in isolated brush border membrane from rat small intestine.
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DOI：
10.1016/s0021-9258(19)44440-2
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发表时间：
1973-01
期刊：
影响因子：
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通讯作者：
U. Hopfer;K. Nelson;J. Perrotto;K. Isselbacher
中科院分区：
文献类型：
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作者：
U. Hopfer;K. Nelson;J. Perrotto;K. Isselbacher
使用Millipore过滤技术，已显示标记的d-和l-葡萄糖的摄取发生在来自大鼠小肠上皮细胞的高度纯化的刷状缘膜上。分离的膜中完整的葡萄糖载体系统被证明如下。（a）d-葡萄糖比l-葡萄糖吸收和释放更快。(b)钠离子增加初始速率和程度ofd-葡萄糖摄取3至5倍，没有其他阳离子显示这种效果。（c）根皮苷抑制d-葡萄糖的摄取和释放。(d)证明了d-葡萄糖的反向转运。(e)d-和L-葡萄糖在长时间孵育后达到相同的摄取水平。(f)高浓度的未标记半乳糖可抑制标记葡萄糖的摄取，反之亦然，膜囊对葡萄糖的摄取代表葡萄糖进入囊内水空间，而不是与膜结合。膜暴露于增加的纤维二糖浓度导致囊内空间的渗透收缩和葡萄糖摄取减少。无限介质渗透压，因此零囊内空间导致无葡萄糖摄取。钠在介质中（但不是在intravesicular空间）刺激DD-葡萄糖transport.It的结论是，孤立的刷状缘膜的肠上皮细胞保留葡萄糖载体系统。报告的发现与以下概念一致：（a）葡萄糖转运通过刷状缘膜代表“易化扩散”;（B）葡萄糖载体依赖于钠离子;（c）高细胞外钠浓度（而非细胞内钠浓度）导致葡萄糖转运增加。
Uptake of labeledd- andl-glucose has been shown to occur with highly purified brush border membranes from the epithelial cells of rat small intestine using a Millipore filtration technique. An intact glucose carrier system in the isolated membranes was demonstrated as evidenced by the following. (a)d-Glucose was taken up and released faster thanl-glucose. (b) Sodium ions increased initial rate and extent ofd-glucose uptake 3- to 5-fold; no other cation showed this effect. (c)d-Glucose uptake and release was inhibited by phlorizin. (d) Countertransport ofd-glucose was demonstrated. (e)d- andl-glucose reached the same level of uptake after prolonged incubation. (f) Uptake of labeledd-glucose was inhibited by higher concentrations of unlabeledd-galactose andvice versa.Glucose uptake by membrane vesicles represented entry into an intravesicular aqueous space rather than binding to the membrane. Exposure of the membrane to increasing cellobiose concentrations led to osmotic shrinkage of the intravesicular space and decreased glucose uptake. Infinite medium osmolarity and therefore zero intravesicular space resulted in no glucose uptake. Sodium in the medium (but not in the intravesicular spaces) stimulatedd-glucose transport.It is concluded that isolated brush border membranes of intestinal epithelial cells retain the glucose carrier system. The reported findings are consistent with the concept that (a) glucose transport across the brush border membrane represents “facilitated diffusion”; (b) the glucose carrier is dependent on sodium ions; and (c) high extracellular, but not intracellular sodium concentrations lead to increased glucose transport.