Brown adipose tissue and diet-induced thermogenesis
Brown adipose tissue and diet-induced thermogenesis
复制标题
棕色脂肪组织和饮食诱导的生热作用
作者：
G. Hervey;G. Tobin
有人提出‘·2在棕色脂肪组织中的’饮食诱导产热‘能使动物驱散过多的能量摄入，从而避免肥胖。这一假说被认为是为了证明生热作用在调节能量平衡方面比控制食物摄入量3更重要的观点是正确的，罗思韦尔和斯托克1的报告已经被媒体(英国广播公司电视节目地平线，1979年12月10日)作为体现与人类肥胖有关的一项重要发现而呈现。我们认为他们的数据和论点不足以支持这一假设，原因如下：(1)第一篇论文基于一项实验，其中一组6只大鼠通过“自助餐厅喂养”(即提供各种美味的食物)4·5持续3周来诱导过度喂养，另一组作为对照。食堂喂养的大鼠以脂肪的形式储存的能量远远低于它们摄取的能量的增加--这种差异被认为是生热作用的证明。我们认为以这种方式推断能量消耗是危险的(见参考文献表1)。1)，特别是在主要感兴趣的量的情况下。(本文在表2中包括了一些氧耗量的样本测量，作为“确认降低的效率”，但能量消耗太不稳定，短的测量在平衡实验中是有用的，而且体重数据的调整使解释变得复杂。)准确测量一段平衡期内的能量摄入、消耗和储存既费力又技术严谨；然而，任何系统误差都会在平衡实验中累积，因此，除非能量平衡的所有三个组成部分都被测量出来，否则精确度无法得到检查。(2)新陈代谢能量摄入(即供应的食物中的能量减去因分散和排泄物造成的损失)不能从食物成分表或先前的测量中可靠地预测：实际材料的炸弹热量测定是必不可少的。这必须特别适用于自助餐厅的喂养，那里提供各种高能量密度的专有食物。
IT has been proposed'· 2 that'diet-induced thermogenesis' in brown adipose tissue enables animals to dissipate excessive intake of energy and so avoid obesity. The hypothesis is claimed to justify the view that thermogenesis is more important in regulation of energy balance than control of food intake3, and the report by Rothwell and Stock 1 has been presented by the media (a BBC Television programme Horizon, 10 December 1979) as embodying an important discovery in relation to human obesity. We consider their data and arguments inadequate to support the hypothesis for the following reasons:(1) The first paper hinges on an experiment in which one group of six rats was induced to overfeed by'cafeteria feeding'(that is, providing a variety of tasty foods) 4• 5 for 3 weeks, with a second group as controls. The amount of energy the cafeteria-fed rats stored as fat was much less than the increase in their intake of energy-this discrepancy supposedly demonstrated thermogenesis. We consider that it is hazardous to infer energy expenditure in this way (see Table 1 of ref. 1), particularly where it is the quantity of primary interest.(The paper includes in Table 2 some sample measurements of oxygen consumption as' confirmation oflowered efficiency', but energy expenditure is too variable for short measurements to be useful in balance experiments, and the adjustment of the data for body weight complicates interpretation.) Accurate measurements of energy intake, expenditure and storage over a balance period are laborious and technically exacting; any systematic errors, however, cumulate in balanceexperiments, thus unless all three components of energy balance are measured there is no check on accuracy.(2) Metabolizable energy intake (that is, the energy in food supplied minus the losses due to scattering and in excreta) cannot be reliably predicted from food composition tables or prior measurements: bomb calorimetry of the actual materials is essential. This must apply particularly to cafeteria feeding, where a variety of proprietary foods of high energy density are offered.