TY - JOUR
T1 - The effects of long- or medium-chain fat diets on glucose tolerance and myocellular content of lipid intermediates in rats.
AU - de Vogel-van den Bosch, J.
AU - Hoeks, J.
AU - Timmers, S.
AU - Houten, S.M.
AU - van Dijk, P.J.
AU - Boon, W.
AU - Van Beurden, D.
AU - Schaart, G.
AU - Kersten, S.
AU - Voshol, P.J.
AU - Wanders, R.J.
AU - Hesselink, M.K.C.
AU - Schrauwen, P.
PY - 2011/4
Y1 - 2011/4
N2 - 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.
AB - 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.
KW - MUSCLE INSULIN-RESISTANCE
KW - SKELETAL-MUSCLE
KW - DIFFERENTIAL OXIDATION
KW - ENERGY-EXPENDITURE
KW - ACIDS
KW - TRIGLYCERIDES
KW - METABOLISM
KW - TRANSPORT
KW - CARNITINE
KW - MECHANISM
U2 - 10.1038/oby.2010.152
DO - 10.1038/oby.2010.152
M3 - Article
C2 - 20595951
SN - 1930-7381
VL - 19
SP - 792
EP - 799
JO - Obesity
JF - Obesity
IS - 4
ER -