In obese rat muscle transport of palmitate is increased and is channeled to triacylglycerol storage despite an increase in mitochondrial palmitate oxidation

Holloway, Graham P.;Benton, Carley R.;Müllen, Klaus;Yoshida, Yuko;Bonen, Arend;et.al.
(2009) American Journal of Physiology: Endocrinology and Metabolism — Vol. 296, n° 4, p. E738-E747 (2009)

Files

pdfdocument.pdf
  • Restricted Access
  • Adobe PDF
  • 865.16 KB
No access

Details

Authors
  • Holloway, Graham P.
    Author
  • Benton, Carley R.UCLouvain
    Author
  • Müllen, Klaus
    Author
  • Yoshida, Yuko
    Author
  • Bonen, Arend
    Author
Show more
Abstract
Holloway GP, Benton CR, Mullen KL, Yoshida Y, Snook LA, Han X-X, Glatz JFC, Luiken JJFP, Lally J, Dyck DJ, Bonen A. In obese rat muscle transport of palmitate is increased and is channeled to triacylglycerol storage despite an increase in mitochondrial palmitate oxidation. Am J Physiol Endocrinol Metab 296: E738-E747, 2009. First published January 13, 2009; doi:10.1152/ajpendo.90896.2008.-Intramuscular triacylglycerol (IMTG) accumulation in obesity has been attributed to increased fatty acid transport and/or to alterations in mitochondrial fatty acid oxidation. Alternatively, an imbalance in these two processes may channel fatty acids into storage. Therefore, in red and white muscles of lean and obese Zucker rats, we examined whether the increase in IMTG accumulation was attributable to an increased rate of fatty acid transport rather than alterations in subsarcolemmal (SS) or intermyo-fibrillar ( IMF) mitochondrial fatty acid oxidation. In obese animals selected parameters were upregulated, including palmitate transport (red: +100%; white: +51%), plasmalemmal FAT/CD36 (red: +116%; white: +115%; not plasmalemmal FABPpm, FATP1, or FATP4), IMTG concentrations (red: similar to 2-fold; white: similar to 4-fold), and mitochondrial content (red +30%). Selected mitochondrial parameters were also greater in obese animals, namely, palmitate oxidation (SS red: +91%; SS white: +26%; not IMF mitochondria), FAT/CD36 (SS: +65%; IMF: +65%), citrate synthase (SS: +19%), and beta-hydroxyacyl-CoA dehydrogenase activities (SS: +20%); carnitine palmitoyltransferase-I activity did not differ. A comparison of lean and obese rat muscles revealed that the rate of change in IMTG concentration was eightfold greater than that of fatty acid oxidation (SS mitochondria), when both parameters were expressed relative to fatty transport. Thus fatty acid transport, esterification, and oxidation (SS mitochondria) are upregulated in muscles of obese Zucker rats, with these effects being most pronounced in red muscle. The additional fatty acid taken up is channeled primarily to esterification, suggesting that upregulation in fatty acid transport as opposed to altered fatty acid oxidation is the major determinant of intramuscular lipid accumulation.
Affiliations

Citations

  • APA
  • Chicago
  • FWB

Holloway, G. P., Benton, C. R., Müllen, K., Yoshida, Y., Snook, L. A., Han, X.-X., Glatz, J. F. C., Luiken, J. J. F. P., Lally, J., Dyck, D. J., & Bonen, A. (2009). In obese rat muscle transport of palmitate is increased and is channeled to triacylglycerol storage despite an increase in mitochondrial palmitate oxidation. American Journal of Physiology: Endocrinology and Metabolism, 296(4), E738-E747. https://doi.org/10.1152/ajpendo.90896.2008 (Original work published 2009)