| DGAT1 is not essential for intestinal triacylglycerol absorption or chylomicron synthesis. | |
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MedLine Citation:
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PMID: 11959864 Owner: NLM Status: MEDLINE |
Abstract/OtherAbstract:
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Dietary triacylglycerols are a major source of energy for animals. The absorption of dietary triacylglycerols involves their hydrolysis to free fatty acids and monoacylglycerols in the intestinal lumen, the uptake of these products into enterocytes, the resynthesis of triacylgylcerols, and the incorporation of newly synthesized triacylglycerols into nascent chylomicrons for secretion. In enterocytes, the final step in triacylglycerol synthesis is believed to be catalyzed primarily through the actions of acyl-CoA:diacylglycerol acyltransferase (DGAT) enzymes. In this study, we analyzed intestinal triacylglycerol absorption and chylomicron synthesis and secretion in DGAT1-deficient (Dgat1(-/-)) mice. Surprisingly, DGAT1 was not essential for quantitative dietary triacylglycerol absorption, even in mice fed a high fat diet, or for the synthesis of chylomicrons. However, Dgat1(-/-) mice had reduced postabsorptive chylomicronemia (1 h after a high fat challenge) and accumulated neutral-lipid droplets in the cytoplasm of enterocytes when chronically fed a high fat diet. These results suggest a reduced rate of triacylglycerol absorption in Dgat1(-/-) mice. Analysis of intestine from Dgat1(-/-) mice revealed activity for two other enzymes, DGAT2 and diacylglycerol transacylase, that catalyze triacylglycerol synthesis and apparently help to compensate for the absence of DGAT1. Our findings indicate that multiple mechanisms for triacylglycerol synthesis in the intestine facilitate triacylglycerol absorption. |
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Authors:
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Kimberly K Buhman; Steven J Smith; Scot J Stone; Joyce J Repa; Jinny S Wong; F F Knapp; Betty J Burri; Robert L Hamilton; Nada A Abumrad; Robert V Farese |
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Publication Detail:
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Type: Journal Article; Research Support, Non-U.S. Gov't; Research Support, U.S. Gov't, Non-P.H.S.; Research Support, U.S. Gov't, P.H.S. Date: 2002-04-16 |
Journal Detail:
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Title: The Journal of biological chemistry Volume: 277 ISSN: 0021-9258 ISO Abbreviation: J. Biol. Chem. Publication Date: 2002 Jul |
Date Detail:
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Created Date: 2002-07-08 Completed Date: 2002-08-12 Revised Date: 2007-11-14 |
Medline Journal Info:
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Nlm Unique ID: 2985121R Medline TA: J Biol Chem Country: United States |
Other Details:
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Languages: eng Pagination: 25474-9 Citation Subset: IM |
Affiliation:
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Gladstone Institute of Cardiovascular Disease, San Francisco, California 94141-9100, USA. |
Export Citation:
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APA/MLA Format Download EndNote Download BibTex |
| MeSH Terms | |
Descriptor/Qualifier:
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Acyltransferases
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genetics,
physiology* Animals Chylomicrons / biosynthesis* Diacylglycerol O-Acyltransferase Gene Expression Intestinal Absorption / physiology* Intestine, Small / metabolism, physiology, ultrastructure Mice Mice, Inbred C57BL Mice, Knockout Triglycerides / metabolism* |
| Grant Support | |
ID/Acronym/Agency:
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DK56084/DK/NIDDK NIH HHS |
| Chemical | |
Reg. No./Substance:
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0/Chylomicrons; 0/Triglycerides; EC 2.3.-/Acyltransferases; EC 2.3.1.20/Dgat1 protein, mouse; EC 2.3.1.20/Diacylglycerol O-Acyltransferase |
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