Yokogoshi H, Theall C L, Wurtman R J
Physiol Behav. 1986;36(5):979-82. doi: 10.1016/0031-9384(86)90464-6.
Weaning (21-day-old; 40-50 g) male rats given simultaneous access to two foods, containing 18% casein and 15 or 70% carbohydrate (dextrin), tended to consume only 29-35% as much protein as carbohydrate (i.e., protein/carbohydrate ratios were 0.29-0.35). With maturation, when animals weighed 100 g or more, about half continued this pattern of nutrient choice, but the others abruptly began to consume considerably larger proportions of protein, exhibiting protein/carbohydrate ratios as high as 0.80-1.00. Each adult animal's protein/carbohydrate ratio tended to vary only slightly (s.e. = 3% of means). Adult protein/carbohydrate ratios were not correlated with fasting brain 5-HT or 5-HIAA levels. These marked differences among rats in eating behavior would not be observed when--as is usually the case--animals are given access to only one diet.
给21日龄（40 - 50克）的断奶雄性大鼠同时提供两种食物，一种含18%酪蛋白和15%碳水化合物（糊精），另一种含18%酪蛋白和70%碳水化合物（糊精），它们倾向于摄入的蛋白质仅为碳水化合物的29 - 35%（即蛋白质/碳水化合物比率为0.29 - 0.35）。随着成熟，当动物体重达到100克或更重时，约一半的动物继续保持这种营养选择模式，但其他动物突然开始摄入比例大得多的蛋白质，蛋白质/碳水化合物比率高达0.80 - 1.00。每只成年动物的蛋白质/碳水化合物比率往往仅略有变化（标准误 = 平均值的3%）。成年动物的蛋白质/碳水化合物比率与空腹时大脑中的5 - 羟色胺（5 - HT）或5 - 羟吲哚乙酸（5 - HIAA）水平无关。当动物像通常那样只食用一种食物时，就不会观察到大鼠在进食行为上的这些显著差异。
