Bernardis L L, Luboshitzky R, Bellinger L L, McEwen G
Int J Obes. 1982;6(4):369-82.
Weanling male Sprague-Dawley rats received bilateral electrolytic lesions in the ventromedial hypothalamic nuclei (VMNL rats); sham-operated rats served as controls. For 28 post-operative d all animals were fed three equicaloric [16.9 kJ/g (4.03 kcal)] diets with different amounts of macronutrients in each (HCD = high-carbohydrate diet, HFD = high-fat diet and HPD = high-protein diet). VMNL rats selected more than controls from HCD (P less than 0.05) and HFD (P less than 0.01) but similar amounts from the HPD. The total intake from all three diets was greater (P less than 0.001) than that of the controls, but in percent of total diet intakes, VMNL selected proportions comparable to the controls. In terms of macronutient intake, VMNL rats ingested more than controls from each (carbohydrate, P less than 0.001; fat, P less than 0.05; protein, P less than 0.01). Again, in percent of total macronutrient intake, they ingested proportions comparable to the controls. Lee Index (P less than 0.001) was greater and body weight gain/kJ (kcal) smaller (P less than 0.001) in VMNL rats than in controls. However, body weight gains were normal. For the following 14 d, one group of VMNL rats and one control group continued to self-select from the three diets while another VMNL and control group received lab chow [14.2 kJ/g (3.39 kcal)]. Analysis of variance showed a lesion effect for the Lee Index (P less than 0.001) and Lee Index gain /kJ(kcal) (P less than 0.01) but body weight gains and caloric intake were normal among the groups, ie the VMNL rats switched to chow decreased their caloric intake to control levels. On sacrifice, white and brown fat percent protein (P less than 0.001 for both), carcass lipid (P less than 0.001) and protein (P less than 0.01) and plasma insulin (P less than 0.001) showed lesion effects, but there were no differences among the groups in plasma glucose, glycerol, total protein and free-fatty acids. Availability of palatable diets immediately following VMN lesion placement in weanling rats will result in hyperphagia that after one month recedes to normophagia, whether the rats are fed palatable or less palatable diets. Availability of a less palatable diet (chow) following presentation of palatable diets will not result in diminished caloric intake, body weight, obesity and hyperinsulinemia.
断奶雄性斯普拉格-道利大鼠接受双侧下丘脑腹内侧核电解损伤（VMNL大鼠）；假手术大鼠作为对照。术后28天，所有动物均喂食三种等热量[16.9 kJ/g（4.03 kcal）]的饮食，每种饮食中宏量营养素的含量不同（HCD = 高碳水化合物饮食，HFD = 高脂肪饮食，HPD = 高蛋白饮食）。VMNL大鼠从HCD（P < 0.05）和HFD（P < 0.01）中选择的量比对照组多，但从HPD中选择的量与对照组相似。三种饮食的总摄入量比对照组大（P < 0.001），但在总饮食摄入量的百分比方面，VMNL大鼠选择的比例与对照组相当。就宏量营养素摄入量而言，VMNL大鼠从每种宏量营养素（碳水化合物，P < 0.001；脂肪，P < 0.05；蛋白质，P < 0.01）中的摄入量均高于对照组。同样，在总宏量营养素摄入量的百分比方面，它们摄入的比例与对照组相当。VMNL大鼠与对照组相比，李氏指数更大（P < 0.001），每千焦（千卡）体重增加更小（P < 0.001）。然而，体重增加是正常的。在接下来的14天里，一组VMNL大鼠和一组对照大鼠继续从三种饮食中自行选择，而另一组VMNL大鼠和对照大鼠则喂食实验室饲料[14.2 kJ/g（3.39 kcal）]。方差分析显示，李氏指数（P < 0.001）和李氏指数每千焦（千卡）增加量（P < 0.01）存在损伤效应，但各组间体重增加和热量摄入正常，即转而食用饲料的VMNL大鼠将热量摄入降低到了对照水平。处死时，白色和棕色脂肪的蛋白质百分比（两者均为P < 0.001）以及胴体脂质（P < 0.001）、蛋白质（P < 0.01）和血浆胰岛素（P < 0.001）显示出损伤效应，但各组间血浆葡萄糖、甘油、总蛋白和游离脂肪酸无差异。断奶大鼠VMN损伤后立即提供可口饮食会导致食欲亢进，一个月后恢复到正常摄食状态，无论大鼠喂食的是可口饮食还是不可口饮食。在提供可口饮食后再提供不可口饮食（饲料）不会导致热量摄入、体重、肥胖和高胰岛素血症的减少。
