Takase S, Goda T
Department of Nutrition, School of Food and Nutritional Sciences, University of Shizuoka, Japan.
J Nutr. 1990 Sep;120(9):969-76. doi: 10.1093/jn/120.9.969.
The effects of various types of dietary fat on brush border membrane-bound enzymes in rat intestinal mucosa were examined. Four groups of five rats were pair-fed defined diets for 10 d. The control group was fed a diet containing 57% sucrose and 2% corn oil as a fixed carbohydrate reference; the three experimental groups received diets containing 57% sucrose and 2% corn oil plus 13% fat in the form of medium-chain triglycerides (MCT) or long-chain triglycerides (LCT) (either lard as a highly saturated fat or corn oil as a highly unsaturated fat). Feeding LCT compared to the control diet, decreased sucrase activity in mucosal brush borders of the duodenum and jejunum. In these segments of MCT-fed rats, sucrase activity was similar to that in the control animals. In another experiment, measuring immunoreactive sucrase-isomaltase in jejunal brush border membranes revealed that feeding a high corn oil diet, but not a high MCT diet, led to a reduction in the sucrase catalytic activity per unit weight of enzyme protein, suggesting that the degradation status of sucrase-isomaltase might be altered by the different types of dietary fats. With MCT feeding, jejunal alkaline phosphatase activity was enhanced to a large extent compared to the activity in other groups. Feeding MCT, compared to lard or corn oil, also increased microvillus phospholipids of the jejunal mucosa. These results suggest that MCT, unlike LCT, do not suppress the activity of mucosal microvillus membrane enzymes in rat small intestine.
研究了不同类型膳食脂肪对大鼠肠黏膜刷状缘膜结合酶的影响。将四组每组五只大鼠配对喂养特定饮食10天。对照组喂食含有57%蔗糖和2%玉米油作为固定碳水化合物参考的饮食；三个实验组接受含有57%蔗糖和2%玉米油加13%以中链甘油三酯（MCT）或长链甘油三酯（LCT）形式存在的脂肪的饮食（LCT为高度饱和脂肪猪油，或高度不饱和脂肪玉米油）。与对照饮食相比，喂食LCT降低了十二指肠和空肠黏膜刷状缘的蔗糖酶活性。在喂食MCT的大鼠的这些肠段中，蔗糖酶活性与对照动物相似。在另一项实验中，测量空肠刷状缘膜中的免疫反应性蔗糖酶 - 异麦芽糖酶发现，喂食高玉米油饮食而非高MCT饮食会导致单位重量酶蛋白的蔗糖酶催化活性降低，这表明不同类型的膳食脂肪可能会改变蔗糖酶 - 异麦芽糖酶的降解状态。与其他组相比，喂食MCT可使空肠碱性磷酸酶活性大幅增强。与猪油或玉米油相比，喂食MCT还增加了空肠黏膜的微绒毛磷脂。这些结果表明，与LCT不同，MCT不会抑制大鼠小肠黏膜微绒毛膜酶的活性。
