Covasa M, Ritter R C
Department of Veterinary and Comparative Anatomy, Pharmacology and Physiology, and Program in Neuroscience, Washington State University, Pullman, Washington 99164, USA.
Am J Physiol. 1999 Jul;277(1):R279-85. doi: 10.1152/ajpregu.1999.277.1.R279.
When rats are maintained on high-fat diets, digestive processes adapt to provide for more efficient digestion and absorption of this nutrient. Furthermore, rats fed high-fat diets tend to consume more calories and gain more weight than rats on a low-fat diet. We hypothesized that, in addition to adaptation of digestive processes, high-fat maintenance diets might result in reduction of sensitivity to the satiating effects of fat digestion products, which inhibit food intake by activating sensory fibers in the small intestine. To test this hypothesis we measured food intake after intestinal infusion of oleic acid or the oligosaccharide maltotriose in rats maintained on a low-fat diet or one of three high-fat diets. We found that rats fed high-fat diets exhibited diminished sensitivity to satiation by intestinal infusion of oleic acid. Sensitivity to the satiation effect of intestinal maltotriose infusion did not differ between groups maintained on the various diets. Reduced sensitivity to oleate infusion was specifically dependent on fat content of the diet and was not influenced by the dietary fiber or carbohydrate content. These results indicate that diets high in fat reduce the ability of fat to inhibit further food intake. Such changes in sensitivity to intestinal fats might contribute to the increased food intake and obesity that occur with high-fat diet regimens.
当给大鼠喂食高脂饮食时，消化过程会发生适应性变化，以更有效地消化和吸收这种营养物质。此外，与喂食低脂饮食的大鼠相比，喂食高脂饮食的大鼠往往会摄入更多热量并增加体重。我们推测，除了消化过程的适应性变化外，高脂维持饮食可能会导致对脂肪消化产物饱腹感作用的敏感性降低，脂肪消化产物通过激活小肠中的感觉纤维来抑制食物摄入。为了验证这一假设，我们在喂食低脂饮食或三种高脂饮食之一的大鼠中，测量了肠道注入油酸或低聚糖麦芽三糖后的食物摄入量。我们发现，喂食高脂饮食的大鼠对肠道注入油酸产生饱腹感的敏感性降低。在不同饮食的大鼠组中，对肠道注入麦芽三糖产生饱腹感的敏感性没有差异。对油酸注入的敏感性降低具体取决于饮食中的脂肪含量，不受膳食纤维或碳水化合物含量的影响。这些结果表明，高脂肪饮食会降低脂肪抑制进一步食物摄入的能力。对肠道脂肪敏感性的这种变化可能导致高脂饮食方案中食物摄入量增加和肥胖。
