Desautels M, Dulos R A
Department of Physiology, College of Medicine, University of Saskatchewan, Saskatoon, Canada.
Am J Physiol. 1990 Mar;258(3 Pt 2):R608-15. doi: 10.1152/ajpregu.1990.258.3.R608.
Mice selected for high body weight (QL522) had increased food intake, body weight gain, and fat deposition relative to mice without weight selection (QL521). Brown adipose tissue (BAT) thermogenic capacity, as determined by the tissue content of protein, DNA, and succinate dehydrogenase and by mitochondrial uncoupling protein content was similar or slightly higher in 2- and 10-mo-old QL522 mice relative to age-matched QL521 mice. When food intake of QL522 mice was restricted to the level of QL521 mice, body weight gain and fat deposition over 28 days were then comparable to those of QL521 mice. Food restriction had no effect on BAT composition of QL522 mice. Both QL521 and QL522 mice increased calorie intake by 40-50% when offered a palatable high-fat supplement (HF), but only QL522 mice increased weight gain and fat deposition significantly. QL521 mice fed a high-fat supplement showed a significant increase in brown fat succinate dehydrogenase content, whereas QL522 mice showed significant increases in brown fat weight, protein, and succinate dehydrogenase content relative to mice fed stock diet. Nonshivering thermogenic capacity, as assessed by norepinephrine-stimulated oxygen uptake in anesthetized animals at 30 degrees C was similar between QL521 and QL522 mice eating stock diet and was significantly increased by the high-fat supplement in both strains. Thus mice selected for high body weight are very susceptible to diet-induced obesity, and we have no evidence that a reduction in brown fat thermogenic capacity contributes to the increased fat deposition of QL522 mice as they grow old or when they are offered palatable energy-dense supplements.
与未进行体重选择的小鼠（QL521）相比，被选作高体重的小鼠（QL522）食物摄入量增加、体重增加且脂肪沉积增多。通过蛋白质、DNA、琥珀酸脱氢酶的组织含量以及线粒体解偶联蛋白含量测定的棕色脂肪组织（BAT）产热能力，在2月龄和10月龄的QL522小鼠中相对于年龄匹配的QL521小鼠相似或略高。当QL522小鼠的食物摄入量被限制到QL521小鼠的水平时，28天内的体重增加和脂肪沉积与QL521小鼠相当。食物限制对QL522小鼠的BAT组成没有影响。当提供可口的高脂肪补充剂（HF）时，QL521和QL522小鼠的卡路里摄入量均增加40 - 50%，但只有QL522小鼠的体重增加和脂肪沉积显著增加。喂食高脂肪补充剂的QL521小鼠棕色脂肪琥珀酸脱氢酶含量显著增加，而与喂食普通饲料的小鼠相比，QL522小鼠棕色脂肪重量、蛋白质和琥珀酸脱氢酶含量显著增加。在30摄氏度下通过麻醉动物中去甲肾上腺素刺激的氧气摄取评估的非颤抖产热能力，在食用普通饲料的QL521和QL522小鼠之间相似，并且在两个品系中高脂肪补充剂均使其显著增加。因此，被选作高体重的小鼠对饮食诱导的肥胖非常敏感，并且我们没有证据表明棕色脂肪产热能力的降低导致QL522小鼠随着年龄增长或当提供可口的能量密集型补充剂时脂肪沉积增加。
