The Effects of Long- or Medium-Chain Fat Diets on Glucose Tolerance and Myocellular Content of Lipid Intermediates in Rats
The Effects of Long- or Medium-Chain Fat Diets on Glucose Tolerance and Myocellular Content of Lipid Intermediates in Rats
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DOI：
10.1038/oby.2010.152
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发表时间：
2011-04-01
期刊：
影响因子：
6.9
通讯作者：
Schrauwen, Patrick
中科院分区：
文献类型：
--
作者：
De Vogel-van den Bosch, Johan;Hoeks, Joris;Schrauwen, Patrick
在高脂肪（HF）喂养时，三酰基甘油（TAG）和酰基肉毒碱在骨骼肌中的积累是脂肪酸摄取和氧化的结果，并且与胰岛素抵抗相关。由于中链脂肪酸（MCFA）优先于长链脂肪酸进行β-氧化，因此我们研究了中链TAG（MCT）和长链TAG（LCT）对肌肉脂质储存和全身葡萄糖耐量的影响。喂食低脂（LF）、HFLCT或等热量HFMCT饲料的大鼠在8周给药期间显示出相似的体重增加。仅HFLCT增加肌细胞TAG（LF、HFLCT和HFMCT分别为42.3 +/-4.9、71.9 +/-6.7和48.5 +/-6.5 μ mol/g，P <0.05）和长链酰基肉毒碱含量（P <0.05）。HF饮食均不增加肌细胞二酰甘油（DAG）含量。腹膜内（IP）葡萄糖耐量试验（1.5 g/kg）显示，与HFLCT喂养大鼠相比，HFMCT组的葡萄糖耐量显著降低（LF、HFLCT和HFMCT的曲线下面积分别为802 +/-40、772 +/-18和886 +/-18，P <0.05）。最后，在LF、HFLCT或HFMCT喂养大鼠之间未观察到餐时胰岛素注射（10 U/kg）后肌细胞胰岛素信号传导的差异。这些结果表明，在没有体重增加的情况下，TAG和酰基肉毒碱在骨骼肌中的积累不会阻碍肌细胞胰岛素信号传导或全身葡萄糖耐受不良。
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 mu mol/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.