Changes of nonelectrolyte permeability in cholesterol-loaded erythrocytes.
Changes of nonelectrolyte permeability in cholesterol-loaded erythrocytes.
复制标题
负载胆固醇的红细胞中非电解质渗透性的变化。
DOI：
10.1016/0005-2736(76)90287-x
复制
发表时间：
1976
期刊：
影响因子：
--
通讯作者：
C. Ruska
中科院分区：
文献类型：
--
作者：
B. Deuticke;C. Ruska
猪和牛红细胞膜胆固醇升高到165%，其正常值的细胞孵育的胆固醇/磷脂酰胆碱分散液有或无血清。膜脂组成的这种改变仅导致对甘油、胆固醇和通过非离子扩散渗透的有机酸的渗透性的轻微（10-40%）降低，尽管额外的胆固醇实际上已掺入脂双层中，如从临界溶血体积测定细胞表面积所示，结合冷冻蚀刻电子显微照片的定量评价。和Deuticke，B.（1974）Biochim. Biophys. Acta 356，125-130）在胆固醇耗尽的细胞中渗透性的显著增加，提出在红细胞膜中，胆固醇对渗透性的显著“特异性”降低仅在胆固醇/极性脂质的摩尔比为0.6时发生。在较高的比例胆固醇影响渗透性只有轻微的，由于一个“非特异性”硬化作用的膜脂相。
Membrane cholesterol in porcine and bovine erythrocytes was elevated up to 165% of its normal value by incubation of the cells in cholesterol/phosphatidylcholine dispersions with or without serum. This alteration of membrane lipid composition brought about only a minor (10–40%) decrease of the permeability to glycerol, erythritol and to organic acids penetrating by non-ionic diffusion, although additional cholesterol had actually been incorporated into the lipid bilayer, as indicated by determinations of cell surface area from the critical hemolytic volume, in combination with quantitative evaluation of freeze-etch electron micrographs.On the basis of this finding and of the previously demonstrated (Grunze, M. and Deuticke, B. (1974) Biochim. Biophys. Acta 356, 125–130) considerable increase of permeability in cholesterol-depleted cells, it is proposed that in the erythrocyte membrane a pronounced “specific” reduction of permeability by cholesterol occurs only up to a molar ratio cholesterol/polar lipid of 0.6. At higher ratios cholesterol affects permeability only slightly, owing to an “unspecific” rigidifying effect on the membrane lipid phase.