DGAT1 is not essential for intestinal triacylglycerol absorption or chylomicron synthesis

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

Research output: Contribution to journalArticlepeer-review

174 Scopus citations

Abstract

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 neutrallipid 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.

Original languageEnglish (US)
Pages (from-to)25474-25479
Number of pages6
JournalJournal of Biological Chemistry
Volume277
Issue number28
DOIs
StatePublished - Jul 12 2002

ASJC Scopus subject areas

  • Biochemistry
  • Molecular Biology
  • Cell Biology

Fingerprint Dive into the research topics of 'DGAT1 is not essential for intestinal triacylglycerol absorption or chylomicron synthesis'. Together they form a unique fingerprint.

Cite this