Williams M A, Tinoco J, Ojakian M A, Clark L
Lipids. 1977 Apr;12(4):386-92. doi: 10.1007/BF02533643.
Responses to refeeding after fasting were studied in male rats fed a purified casein-sucrose diet containing 5% safflower oil. After a 48 hr fast, the rats were fed either the same diet or the same diet minus oil (fat-free diet). These experiments were designed to distinguish changes due to fasting and refeeding alone without a change of diet from those changes caused by refeeding a diet of different composition. In the first experiment, rats were refed for 3 or 7 days. In rats refed either diet, liver glucose-6-phosphate dehydrogenase (G6PD) activity was elevated above refasting levels, but after 7 days, activity in rats refed the 5% safflower oil diet was significantly lower than in those refed the fat-free diet. The amount of liver arachidonate in rats refed the safflower oil diet was the same during refeeding as before fasting. In the second experiment, rats were refed the fat-free diet for 1, 2, 3, or 7 days. Liver G6PD and fatty acid synthetase were measured, as well as fatty acids in liver total lipids and phospholipids. G6PD activity increased above prefasting levels after one day refeeding and continued to increase for 7 days. Fatty acid synthetase activity increased for the first 3 days of refeeding, with no additional increase after 7 days. In all rats refed the fat-free diet, the proportions of arachidonate and linoleate in liver phospholipids diminished with time, and eicosatrienoate appeared. These results show that (a) maintenance of liver phospholipid arachidonate did not prevent increased G6PD activity in early refeeding, but the elevated G6PD activity later declined when phospholipid arachidonate was maintained by feeding a source of linoleate; (b) the metabolic state of fasted-refed rats had not returned to prefasting conditions even after 7 days of refeeding a linoleate-rich diet to which the rats were adapted before fasting.
对禁食后再喂食的反应在喂食含5%红花油的纯化酪蛋白 - 蔗糖饮食的雄性大鼠中进行了研究。禁食48小时后，给大鼠喂食相同饮食或相同但不含油的饮食（无脂饮食）。这些实验旨在区分仅由禁食和再喂食引起的变化（饮食无变化）与由喂食不同成分饮食引起的变化。在第一个实验中，大鼠再喂食3天或7天。在再喂食任何一种饮食的大鼠中，肝脏葡萄糖 - 6 - 磷酸脱氢酶（G6PD）活性高于再禁食水平，但7天后，再喂食含5%红花油饮食的大鼠的活性显著低于再喂食无脂饮食的大鼠。再喂食红花油饮食的大鼠肝脏花生四烯酸的量在再喂食期间与禁食前相同。在第二个实验中，大鼠再喂食无脂饮食1、2、3或7天。测量了肝脏G6PD和脂肪酸合成酶，以及肝脏总脂质和磷脂中的脂肪酸。再喂食一天后，G6PD活性高于禁食前水平，并持续增加7天。脂肪酸合成酶活性在再喂食的前3天增加，7天后没有进一步增加。在所有再喂食无脂饮食的大鼠中，肝脏磷脂中花生四烯酸和亚油酸的比例随时间减少，并且出现了二十碳三烯酸。这些结果表明：（a）肝脏磷脂花生四烯酸的维持并不能阻止早期再喂食时G6PD活性的增加，但当通过喂食亚油酸来源维持磷脂花生四烯酸时，升高的G6PD活性随后下降；（b）即使在禁食前使大鼠适应富含亚油酸的饮食再喂食7天后，禁食 - 再喂食大鼠的代谢状态也未恢复到禁食前状态。
