Armitage G, Harris R B, Hervey G R, Tobin G
J Physiol. 1984 May;350:197-207. doi: 10.1113/jphysiol.1984.sp015196.
The energy expenditure of normal and congenitally obese adult female Zucker rats has been measured by continuous indirect calorimetry for periods of 3-10 days at ambient temperatures varied from 30 to 5 degrees C. Rectal temperatures were also recorded. Exposure to cold caused no ill-effects in normal or obese rats. The rectal temperatures of obese rats were about 1 degree C lower than those of normal rats. The rectal temperatures of normal rats did not change measurably with ambient temperature; in obese rats rectal temperature rose slightly as ambient temperature fell. In normal and obese rats, energy expenditure showed a smooth, steeply sloping, negative relationship to ambient temperature. Energy expenditure per rat was higher in obese than in normal rats at all temperatures. The two slightly curvilinear regressions were nearly 'parallel', with a separation of about 40 kJ/day per rat at the mid-point. This study therefore does not confirm suggestions that obese Zucker rats suffer from a defect in the level of energy expenditure, or in their capacity to increase it when exposed to cold. It is suggested that in both normal and obese rats the level of energy expenditure was determined by thermoregulatory control. The greater heat production of obese rats may have been a response to their lower core temperature. A steady state in which greater heat production is associated with lower core temperature implies lower insulation between body core and surface. This could be due to greater blood flow.
通过连续间接热量测定法，在环境温度从30摄氏度变化到5摄氏度的条件下，对正常成年雌性和先天性肥胖成年雌性Zucker大鼠的能量消耗进行了为期3至10天的测量。同时还记录了直肠温度。暴露于寒冷环境对正常或肥胖大鼠均未产生不良影响。肥胖大鼠的直肠温度比正常大鼠低约1摄氏度。正常大鼠的直肠温度不会随环境温度发生明显变化；而肥胖大鼠的直肠温度会随着环境温度的降低而略有升高。在正常和肥胖大鼠中，能量消耗与环境温度呈现出平滑、陡峭倾斜的负相关关系。在所有温度下，每只肥胖大鼠的能量消耗均高于正常大鼠。两条略呈曲线的回归线几乎“平行”，在中点处每只大鼠的能量消耗相差约40千焦/天。因此，本研究并未证实关于肥胖Zucker大鼠在能量消耗水平或暴露于寒冷环境时增加能量消耗能力存在缺陷的说法。研究表明，正常和肥胖大鼠的能量消耗水平均由体温调节控制决定。肥胖大鼠产生更多热量可能是对其较低核心体温的一种反应。一种热量产生增加与核心体温降低相关的稳态意味着身体核心与体表之间的隔热性较低。这可能是由于血流量增加所致。
