亮氨酸对高脂膳食喂养大鼠胰岛素敏感性的影响

目的探讨亮氨酸(Leucine,Leu)对高脂膳食诱导的胰岛素抵抗(insulin resistance,IR)大鼠胰岛素敏感性的影响。方法给正常大鼠和高脂膳食大鼠分别补充0,1.5%,3.0%和4.5%水平的亮氨酸24w。进行胰岛素耐量实验。检测血清Leu水平、血糖,血胰岛素,计算胰岛素抵抗指数(HOMA-IR)。Western blot检测肝脏哺乳动物雷帕霉素靶蛋白(mammalian target of rapamycin,mTOR)及磷酸化mTOR表达水平。结果高脂喂养大鼠Leu干预组胰岛素耐量曲线下面积值(AUC)明显降低,血胰岛素水平及HOMA-IR明显降低。Leu可显著增强胰岛素刺激后肝脏pSer2448 mTOR的表达。Leu补充对正常大鼠上述指标无明显影响。结论膳食补充Leu可以增强高脂喂养胰岛素抵抗大鼠的胰岛素敏感性。营养学报,2012,34(6):545-548,552]

EFFECT OF LEUCINE ON INSULIN SENSITIVITY IN RATS FED A HIGH-FAT DIET

Objective To evaluate the effects of leucine on insulin sensitivity in rats fed a high-fat diet.Method Rats were fed normal chow diet or high-fat diets supplemented with 1.5%,3.0% and 4.5% leucine for 24 w.Insulin tolerance test(ITT) was performed.The serum leucine,glucose and insulin levels were detected and homeostasis model assessment of insulin resistance index(HOMA-IR) was calculated.Western bloting was used to detect mammalian target of rapamycin(mTOR) and phosphor-mTOR(pSer 2448) expression in liver.Results Compared with the high-fat diet,the areas under the curve(AUC) of ITT,serum insulin levels and HOMA-IR all decreased significantly in rats on high-fat diets supplemented with leucine.After insulin stimulation,leucine could significantly enhance mTOR phosphoration at serine 2448 in liver.Conclusion Leucine supplementation can improve the insulin sensitivity in rats fed a high-fat diet.ACTA NUTRIMENTA SINICA,2012,34(6):545-548,552]