The effects of long- or medium-chain fat diets on glucose tolerance and myocellular content of lipid intermediates in rats.

J. de Vogel-van den Bosch, J. Hoeks, S. Timmers, S.M. Houten, P.J. van Dijk, W. Boon, D. Van Beurden, G. Schaart, S. Kersten, P.J. Voshol, R.J. Wanders, M.K.C. Hesselink, P. Schrauwen

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Abstract

Accumulation of triacylglycerols (TAGs) and acylcarnitines in skeletal muscle upon high-fat (HF) feeding is the resultant of fatty acid uptake and oxidation and is associated with insulin resistance. As medium-chain fatty acids (MCFAs) are preferentially beta-oxidized over long-chain fatty acids, we examined the effects of medium-chain TAGs (MCTs) and long-chain TAGs (LCTs) on muscle lipid storage and whole-body glucose tolerance. Rats fed a low-fat (LF), HFLCT, or an isocaloric HFMCT diet displayed a similar body weight gain over 8 weeks of treatment. Only HFLCT increased myocellular TAG (42.3 +/- 4.9, 71.9 +/- 6.7, and 48.5 +/- 6.5 micromol/g for LF, HFLCT, and HFMCT, respectively, P < 0.05) and long-chain acylcarnitine content (P < 0.05). Neither HF diet increased myocellular diacylglycerol (DAG) content. Intraperitoneal (IP) glucose tolerance tests (1.5 g/kg) revealed a significantly decreased glucose tolerance in the HFMCT compared to the HFLCT-fed rats (802 +/- 40, 772 +/- 18, and 886 +/- 18 area under the curve for LF, HFLCT, and HFMCT, respectively, P < 0.05). Finally, no differences in myocellular insulin signaling after bolus insulin injection (10 U/kg) were observed between LF, HFLCT, or HFMCT-fed rats. These results show that accumulation of TAGs and acylcarnitines in skeletal muscle in the absence of body weight gain do not impede myocellular insulin signaling or whole-body glucose intolerance.
Original languageEnglish
Pages (from-to)792-799
Number of pages8
JournalObesity
Volume19
Issue number4
DOIs
Publication statusPublished - Apr 2011

Keywords

  • MUSCLE INSULIN-RESISTANCE
  • SKELETAL-MUSCLE
  • DIFFERENTIAL OXIDATION
  • ENERGY-EXPENDITURE
  • ACIDS
  • TRIGLYCERIDES
  • METABOLISM
  • TRANSPORT
  • CARNITINE
  • MECHANISM

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