High expression of thyroid hormone receptors and mitochondrial glycerol-3-phosphate dehydrogenase in the liver is linked to enhanced fatty acid oxidation in Lou/C, a rat strain resistant to obesity

J Biol Chem. 2009 Feb 13;284(7):4308-16. doi: 10.1074/jbc.M806187200. Epub 2008 Dec 2.

Abstract

Besides its well recognized role in lipid and carbohydrate metabolisms, glycerol is involved in the regulation of cellular energy homeostasis via glycerol-3-phosphate, a key metabolite in the translocation of reducing power across the mitochondrial inner membrane with mitochondrial glycerol-3-phosphate dehydrogenase. Here, we report a high rate of gluconeogenesis from glycerol and fatty acid oxidation in hepatocytes from Lou/C, a peculiar rat strain derived from Wistar, which is resistant to age- and diet-related obesity. This feature, associated with elevated cellular respiration and cytosolic ATP/ADP and NAD(+)/NADH ratios, was linked to a high expression and activity of mitochondrial glycerol-3-phosphate dehydrogenase. Interestingly, this strain exhibited high expression and protein content of thyroid hormone receptor, whereas circulating thyroid hormone levels were slightly decreased and hepatic thyroid hormone carrier MCT-8 mRNA levels were not modified. We propose that an enhanced liver thyroid hormone receptor in Lou/C may explain its unique resistance to obesity by increasing fatty acid oxidation and lowering liver oxidative phosphorylation stoichiometry at the translocation of reducing power into mitochondria.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Diphosphate / metabolism
  • Adenosine Triphosphate / metabolism
  • Animals
  • Fatty Acids / metabolism*
  • Gluconeogenesis / physiology
  • Glycerol / metabolism
  • Glycerolphosphate Dehydrogenase / metabolism*
  • Glycerophosphates / metabolism
  • Hepatocytes / metabolism*
  • Male
  • Mitochondria, Liver / metabolism*
  • Monocarboxylic Acid Transporters
  • NAD / metabolism
  • Obesity*
  • Oxidation-Reduction
  • Rats
  • Rats, Wistar
  • Receptors, Thyroid Hormone / metabolism*
  • Species Specificity

Substances

  • Fatty Acids
  • Glycerophosphates
  • Monocarboxylic Acid Transporters
  • Receptors, Thyroid Hormone
  • monocarboxylate transporter 8, rat
  • NAD
  • Adenosine Diphosphate
  • Adenosine Triphosphate
  • Glycerolphosphate Dehydrogenase
  • Glycerol