Diacylglycerol acyltransferase-1 inhibition enhances intestinal fatty acid oxidation and reduces energy intake in rats

J Lipid Res. 2013 May;54(5):1369-84. doi: 10.1194/jlr.M035154. Epub 2013 Feb 28.

Abstract

Acyl CoA:diacylglycerol acyltransferase-1 (DGAT-1) catalyzes the final step in triacylglycerol (TAG) synthesis and is highly expressed in the small intestine. Because DGAT-1 knockout mice are resistant to diet-induced obesity, we investigated the acute effects of intragastric (IG) infusion of a small molecule diacylglycerol acyltransferase-1 inhibitor (DGAT-1i) on eating, circulating fat metabolites, indirect calorimetry, and hepatic and intestinal expression of key fat catabolism enzymes in male rats adapted to an 8 h feeding-16 h deprivation schedule. Also, the DGAT-1i effect on fatty acid oxidation (FAO) was investigated in enterocyte cell culture models. IG DGAT-1i infusions reduced energy intake compared with vehicle in high-fat diet (HFD)-fed rats, but scarcely in chow-fed rats. IG DGAT-1i also blunted the postprandial increase in serum TAG and increased β-hydroxybutyrate levels only in HFD-fed rats, in which it lowered the respiratory quotient and increased intestinal, but not hepatic, protein levels of Complex III of the mitochondrial respiratory chain and of mitochondrial hydroxymethylglutaryl-CoA synthase. Finally, the DGAT-1i enhanced FAO in CaCo2 (EC50 = 0.3494) and HuTu80 (EC50 = 0.00762) cells. Thus, pharmacological DGAT-1 inhibition leads to an increase in intestinal FAO and ketogenesis when dietary fat is available. This may contribute to the observed eating-inhibitory effect.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Acyl Coenzyme A / metabolism
  • Animals
  • Diacylglycerol O-Acyltransferase / antagonists & inhibitors
  • Diacylglycerol O-Acyltransferase / metabolism*
  • Diet, High-Fat
  • Electron Transport Complex III / metabolism
  • Energy Intake
  • Fatty Acids / metabolism*
  • Humans
  • Intestinal Mucosa / metabolism*
  • Intestines / enzymology
  • Liver / enzymology
  • Liver / metabolism
  • Male
  • Oxidation-Reduction*
  • Rats

Substances

  • Acyl Coenzyme A
  • Fatty Acids
  • Dgat1 protein, rat
  • Diacylglycerol O-Acyltransferase
  • Electron Transport Complex III