期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：1977
卷号：74
期号：4
页码：1538-1542
DOI：10.1073/pnas.74.4.1538
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：We studied the exchange of cholesterol between radioactively labeled plasma and human erythrocytes. Results from experiments in which [3H]cholesterol and [14C]-cholesterol were exchanged sequentially into the cells and back out into unlabeled plasma, showed that transmembrane movement of cholesterol occurred with a half-time that was either less than 50 min or greater than 10 days. To obtain further information about the transmembrane movement of cholesterol, we used a technique [Jacobson, B. S. & Branton, D. (1977) Science 195, 302-304] for exposure of the cytoplasmic surface of erythrocyte membranes. This method involved the ionic attachment of erythrocytes to derivatized glass beads followed by disruption of the cells, leaving the beads covered by membrane with the cytoplasmic surface exposed [3H]Cholesterol was exchanged into intact erythrocytes which then were attached to beads. The beads with attached membrane were incubated with phospholipid-cholesterol vesicles and the exchange of cholesterol between the membrane cytoplasmic surface and vesicles was studied. We found that [3H]cholesterol was present at the cytoplasmic surface, indicating that transmembrane movement of cholesterol had occurred within the 2.5 hr required to complete the experiment. This result suggests that the more rapid rate of transmembrane cholesterol movement, inferred from the experiments described above, is the one that applies.
