| Class B scavenger receptor-mediated intestinal absorption of dietary beta-carotene and cholesterol. | |
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MedLine Citation:
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PMID: 15766282 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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There is now a general consensus that the intestinal absorption of water-insoluble, dietary lipids is protein-mediated, but the assignment of protein(s) to this function is still a matter of debate. To address this issue, we measured beta-carotene and cholesterol absorption in wild-type and SR-BI knockout mice and the uptake of these lipids in vitro using brush border membrane (BBM) vesicles. From the comparison of the in vivo and in vitro results we conclude that both BBM-resident class B scavenger receptors, SR-BI and CD36, can facilitate the absorption of beta-carotene and cholesterol. SR-BI is essential for beta-carotene absorption, at least in mice on a high fat diet. This is due to the fact that the absorption of beta-carotene is restricted to the duodenum and SR-BI is the predominant receptor in the mouse duodenum. In contrast, SR-BI may be involved but is not essential for cholesterol absorption in the small intestine. The question of whether SR-BI contributes to cholesterol absorption in vivo is still unresolved. Transfection of COS-7 cells with SR-BI or CD36 confers on these cells lipid uptake properties closely resembling those of enterocytes and BBM vesicles. Both scavenger receptors facilitate the uptake of dietary lipids such as beta-carotene, free and esterified cholesterol, phospholipids, and fatty acids into COS-7 cells. This lipid uptake is effected from three different lipid donor particles: mixed bile salt micelles, phospholipid small unilamellar vesicles, and trioleoylglycerol emulsions which are all likely to be present in the small intestine. Ezetimibe, a representative of a new class of drugs that inhibit intestinal cholesterol absorption, blocks SR-BI- and CD36-facilitated uptake of cholesterol into COS-7 cells. |
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Authors:
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Ariëtte van Bennekum; Moritz Werder; Stephen T Thuahnai; Chang-Hoon Han; Phu Duong; David L Williams; Philipp Wettstein; Georg Schulthess; Michael C Phillips; Helmut Hauser |
Publication Detail:
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Type: Comparative Study; Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, P.H.S. |
Journal Detail:
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Title: Biochemistry Volume: 44 ISSN: 0006-2960 ISO Abbreviation: Biochemistry Publication Date: 2005 Mar |
Date Detail:
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Created Date: 2005-03-15 Completed Date: 2005-05-25 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 0370623 Medline TA: Biochemistry Country: United States |
Other Details:
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Languages: eng Pagination: 4517-25 Citation Subset: IM |
Affiliation:
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Children's Hospital of Philadelphia and University of Pennsylvania School of Medicine, Philadelphia, Pennsylvania 19104-4318, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Animal Feed* Animals Anticholesteremic Agents / administration & dosage Antigens, CD36 / genetics, metabolism, physiology Azetidines / administration & dosage COS Cells Cercopithecus aethiops Cholesterol, Dietary / administration & dosage, antagonists & inhibitors, metabolism* Female Intestinal Absorption* / drug effects, genetics Intestine, Small / chemistry, metabolism Male Mice Mice, Inbred C57BL Mice, Knockout Microvilli / metabolism Rabbits Receptors, Immunologic / deficiency, genetics, metabolism, physiology* Receptors, Scavenger Scavenger Receptors, Class B Transfection beta Carotene / administration & dosage, antagonists & inhibitors, metabolism* |
| Grant Support | |
ID/Acronym/Agency:
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HL22633/HL/NHLBI NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Anticholesteremic Agents; 0/Antigens, CD36; 0/Azetidines; 0/Cholesterol, Dietary; 0/Receptors, Immunologic; 0/Receptors, Scavenger; 0/Scavenger Receptors, Class B; 163222-33-1/ezetimibe; 7235-40-7/beta Carotene |
From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine
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