Pagliassotti M J, Knobel S M, Shahrokhi K A, Manzo A M, Hill J O
Department of Molecular Physiology, Vanderbilt University School of Medicine, Nashville, Tennessee 37232.
Am J Physiol. 1994 Sep;267(3 Pt 2):R659-64. doi: 10.1152/ajpregu.1994.267.3.R659.
The purpose of the present study was to characterize the time course of adaptation (i.e., circulating metabolites and hormones, fat pad mass, lipoprotein lipase) to a high-fat diet in obesity-prone (OP) and obesity-resistant (OR) male Wistar rats. Delineation of OP and OR was based on body weight gain (upper tertile for OP; lower tertile for OR) after 1 wk on a high-fat diet (60% of kcal from corn oil). Rats were killed after 1, 2, or 5 wk of the dietary period. Increased body weight and percent body fat in OP rats at 1 wk could not be accounted for by increased retroperitoneal or epididymal fat pad weight. Plasma nonesterified fatty acids and triglycerides, as well as blood concentrations of glucose, lactate, and glycerol, were similar throughout the study. Plasma insulin was significantly greater in OP vs. OR rats and low-fat diet (LFD; 20% of kcal from corn oil) controls at 5 wk only, and blood beta-hydroxybutyrate (mM) was significantly higher in OR compared with OP and LFD rats at 1, 2, and 5 wk. Lipoprotein lipase mRNA and activity were significantly greater in epididymal fat pad and significantly lower in gastrocnemius muscle of OP vs. OR rats at 1 wk. Results suggest that early (i.e., 1 wk) differences in body weight and fat weight between OP and OR rats are not due to fat deposition in retroperitoneal or epididymal fat depots, and tissue-specific changes in LPL (increase in epididymal fat pad and decrease in gastrocnemius muscle) that occur in OP compared with OR rats after 1 wk on a high-fat diet provide a metabolic environment favoring fat storage.
本研究的目的是描述肥胖倾向（OP）和肥胖抵抗（OR）雄性Wistar大鼠对高脂饮食的适应时间进程（即循环代谢物和激素、脂肪垫质量、脂蛋白脂肪酶）。根据高脂饮食（玉米油提供60%千卡热量）1周后体重增加情况（OP为上三分位数；OR为下三分位数）来划分OP和OR。在饮食期1、2或5周后处死大鼠。OP大鼠在1周时体重增加和体脂百分比增加不能用腹膜后或附睾脂肪垫重量增加来解释。在整个研究过程中，血浆非酯化脂肪酸和甘油三酯以及血液中葡萄糖、乳酸和甘油的浓度相似。仅在5周时，OP大鼠的血浆胰岛素显著高于OR大鼠和低脂饮食（LFD；玉米油提供20%千卡热量）对照组，并且在1、2和5周时，OR大鼠的血液β-羟基丁酸（毫摩尔）显著高于OP和LFD大鼠。在1周时，OP大鼠附睾脂肪垫中的脂蛋白脂肪酶mRNA和活性显著高于OR大鼠，而腓肠肌中的则显著低于OR大鼠。结果表明，OP和OR大鼠在体重和脂肪重量上的早期（即1周）差异并非由于腹膜后或附睾脂肪库中的脂肪沉积，并且与OR大鼠相比，OP大鼠在高脂饮食1周后发生的脂蛋白脂肪酶组织特异性变化（附睾脂肪垫增加而腓肠肌减少）提供了有利于脂肪储存的代谢环境。
