Effect of different type of high fat diets on glycogen loading

为探讨高脂饮食对大鼠糖原负荷的影响，将雄性Wistar大鼠分为低脂饮食(13%热量为脂肪)和高脂肪饲料(60%热量为脂肪)。他们随意进食5周，在隔夜禁食后，两组都进行了两个小时的游泳锻炼，以消耗肌肉糖原。游泳结束后，随机给予高碳水化合物饲料和5%蔗糖溶液。用戊巴比妥钠麻醉大鼠，分别于运动前、运动后即刻、运动后4h、运动后24小时解剖股三头肌和股外侧肌。高脂饮食组大鼠附睾脂肪垫重量、血浆甘油三酯和游离脂肪酸水平显著高于低脂饮食组(P&lt；0.001)，运动前高脂饮食降低肌糖原浓度，但高脂饮食诱导柠檬酸合成酶和3-羟基酰辅酶A脱氢酶活性升高，两组糖原浓度在运动后即刻耗竭，运动后24小时恢复正常。这些结果提示，长期饲喂高脂饮食有损于糖原负荷的作用。

The purpose of this study was to determine the effect of high fat diet on glycogen loading in rats, Male Wistar rats were assigned to low fat diet (13% calories as fat) and a high fat diet (60% calories as fat). They ate their diets ad libitum for 5 weeks, After an overnight fast, both groups were exercised by using a two hours swimming protocol to deplete muscle glycogen. After the swimming, rats were given a high carbohydrate diet and 5% sucrose solution ad libitum. Rats were anesthetized with pentobarbital sodium, and the triceps and vastus lateralis muscles were dissected out before, immediately after, 4h after and 24h after exercise. Epididymal fat pad weight, plasma triglyceride and free fatty acids were significantly (P<0.001) higher in the high fat diet group than in the low fat group, Although the high fat diet decreased muscle glycogen concentration before exercise, the high fat diet induced increases in citrate synthase and 3-hydroxyacyl CoA dehydogenase activities, Glycogen concentration in both groups were depleted immediately after the exercise and recovered to normal level 24h after exercise. These results suggest that long term feeding of high fat diet harm the effect of glycogen loading.