Cao Heping, Hininger-Favier Isabelle, Kelly Meghan A, Benaraba Rachida, Dawson Harry D, Coves Sara, Roussel Anne M, Anderson Richard A
Nutrient Requirements and Functions Laboratory, Beltsville Human Nutrition Research Center, Agricultural Research Service, U.S. Department of Agriculture, Beltsville, Maryland 20705, USA.
J Agric Food Chem. 2007 Jul 25;55(15):6372-8. doi: 10.1021/jf070695o. Epub 2007 Jul 6.
Green tea has antidiabetic, antiobesity, and anti-inflammatory activities in animal models, but the molecular mechanisms of these effects have not been fully understood. Quantitative real-time polymerase chain reaction (PCR) was used to investigate the relative expression levels and the effects of green tea (1 and 2 g solid extract/kg diet) on the expression of glucose transporter family genes (Glut1/Slc2a1, Glut2/Slc2a2, Glut3/Slc2a3, and Glut4/Slc2a4) and insulin signaling pathway genes (Ins1, Ins2, Insr, Irs1, Irs2, Akt1, Grb2, Igf1, Igf2, Igf1r, Igf2r, Gsk3b, Gys1, Pik3cb, Pik3r1, Shc1, and Sos1) in liver and muscle of rats fed a high-fructose diet known to induce insulin resistance and oxidative stress. Glut2 and Glut4 were the major Glut mRNAs in rat liver and muscle, respectively. Green tea extract (1 g) increased Glut1, Glut4, Gsk3b, and Irs2 mRNA levels by 110, 160, 30, and 60% in the liver, respectively, and increased Irs1 by 80% in the muscle. Green tea extract (2 g) increased Glut4, Gsk3b, and Pik3cb mRNA levels by 90, 30, and 30% but decreased Shc1 by 60% in the liver and increased Glut2, Glut4, Shc1, and Sos1 by 80, 40, 60, and 50% in the muscle. This study shows that green tea extract at 1 or 2 g/kg diet regulates gene expression in the glucose uptake and insulin signaling pathway in rats fed a fructose-rich diet.
绿茶在动物模型中具有抗糖尿病、抗肥胖和抗炎活性，但其作用的分子机制尚未完全明确。采用定量实时聚合酶链反应（PCR）研究绿茶（1克和2克固体提取物/千克饮食）对高果糖饮食喂养的大鼠肝脏和肌肉中葡萄糖转运蛋白家族基因（Glut1/Slc2a1、Glut2/Slc2a2、Glut3/Slc2a3和Glut4/Slc2a4）以及胰岛素信号通路基因（Ins1、Ins2、Insr、Irs1、Irs2、Akt1、Grb2、Igf1、Igf2、Igf1r、Igf2r、Gsk3b、Gys1、Pik3cb、Pik3r1、Shc1和Sos1）相对表达水平的影响，高果糖饮食已知会诱导胰岛素抵抗和氧化应激。Glut2和Glut4分别是大鼠肝脏和肌肉中主要的Glut mRNA。绿茶提取物（1克）使肝脏中Glut1、Glut4、Gsk3b和Irs2的mRNA水平分别增加110%、160%、30%和60%，使肌肉中Irs1增加80%。绿茶提取物（2克）使肝脏中Glut4、Gsk3b和Pik3cb的mRNA水平增加90%、30%和30%，但使Shc1降低60%，使肌肉中Glut2、Glut4、Shc1和Sos1分别增加80%、40%、60%和50%。本研究表明，1或2克/千克饮食的绿茶提取物可调节高果糖饮食喂养大鼠葡萄糖摄取和胰岛素信号通路中的基因表达。
