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：1980
卷号：77
期号：7
页码：4349-4353
DOI：10.1073/pnas.77.7.4349
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：The uptake and catabolism of lamellar complexes of rat 125I-labeled apolipoprotein (apo) E with egg lecithin were increased severalfold in perfused livers of rats given large amounts of 17 alpha-ethynylestradiol for 5 days. Estrogen-stimulated uptake of lamellar complexes of human apo E that contained all of the major normally occurring "isoforms" of the protein (apo E-1, E-2, E-3, and E-4) was comparable to that of rat apo E. By contrast, uptake of complexes containing apo E from individuals with familial dysbetalipoproteinemia (dys beta LP; characterized by a lack of apo E-3 and E-4) was stimualted to a much smaller extent. With complexes containing individual isoforms of human apo E, it was shown that estrogen-stimulated hepatic uptake was largely confined to apo E-3 and E-4; uptake of apo E-2 from normolipoproteinemic or dys beta LP individuals, or of apo E-1 from the latter, was stimulated little or not at all. When considered in the light of available information about the hepatic uptake of lipoproteins and the metabolic defect in familial dys beta LP, these results are consistent with the following hypothesis: (i) apo E comprises an essential component of the site for normal recognition of remnants of triglyceride-rich lipoproteins by a specific hepatic receptor; (ii) accumulation of remnant lipoproteins in familial dys beta LP is caused by lack of apo E-3 and E-4, which are the forms of this protein that are primarily recognized by the receptor; and (iii) the normal conversion of remnants of very low density lipoproteins to low density lipoproteins is mediated by the hepatic remnant receptor.
