Regulation of rodent energy metabolism, body weight and composition

一项初步研究表明，在雄性C57BL/6小鼠中，自由摄入高脂肪饮食加液体Ensure（14%蛋白质、22%脂肪和64%碳水化合物）能够诱导严重肥胖。4周后，喂食高脂加Ensure （N = 6）的小鼠体重比喂食标准饲料（24%蛋白质，12%脂肪，64%碳水化合物）的对照组（N = 6）增加45%，脂肪量增加470%。单独喂食高脂肪食物（14%蛋白质，59%脂肪，27%碳水化合物）的小鼠（N = 6），体重和脂肪量分别比正常对照组增加了35%和370%。食用致肥性食物的动物摄入的卡路里最多，但在4周后，当将饮食改为鼠粮时，它们的食物摄入量急剧减少，导致体重和脂肪量在另外4周后接近控制值。这些结果表明，饮食引起的肥胖不是永久性的，一旦肥胖环境被消除，可能会逆转。

A pilot study was conducted that demonstrated the ability of free access to a high-fat diet plus liquid Ensure (14% protein, 22% fat, and 64% carbohydrate) to induce severe obesity in male C57BL/6 mice. After 4 weeks, mice fed high fat plus Ensure (N = 6) had a 45% greater body weight and 470% greater fat mass than the control group fed a standard chow diet (24% protein, 12% fat, 64% carbohydrate) (N = 6). Mice fed with a high fat diet alone (14% protein, 59% fat, and 27% carbohydrate) (N = 6) increased body weight and fat mass by 35% and 370%, respectively, versus the chow-fed controls. The animals on the obesigenic diets ate the most calories, but after 4 weeks when the diets were switched to chow there was a dramatic decrease in food intake causing body weight and fat mass to approach control values after 4 additional weeks. These results suggested that diet-induced obesity is not permanent and may be reversed once the obesigenic environment is removed. We are presently conducting a full experiment using a longer period of obesity induction before switching the diets to standard chow. Furthermore, we are assessing changes of energy expenditure, adipocyte size distributions in various fat depots, inflammatory markers, various endocrine signals, insulin sensitivity, glucose and glycerol turnover, as well as organ mass changes during the induction and reversal of obesity. Various tissues are being collected for subsequent analysis of gene expression and protein changes.