Geiser F, Körtner G, Schmidt I
Zoology, School of Biological Sciences, University of New England, Armidale, New South Wales 2351, Australia.
Am J Physiol. 1998 Nov;275(5):R1627-32. doi: 10.1152/ajpregu.1998.275.5.R1627.
Leptin plays an important role in regulating body fat stores of placental mammals, but the contribution of changes in energy expenditure to this adjustment remains controversial. We were interested in how recombinant murine leptin would affect metabolic rate (MR) and body temperature (Tb) of a marsupial mammal (Sminthopsis macroura, 25 g) known to display daily torpor but lacking thermogenetically active brown adipose tissue. In a group of eight animals deprived of food for 1 day at 18 degreesC, leptin treatment halved the duration of torpor bouts (time at Tb < 30 degreesC) and raised the average daily minimum Tb by 4.5 degreesC and minimum MR by 2.2-fold. Leptin treatment thus increased daily energy expenditure by 9%, although MR and Tb during the activity phase were not raised. Body mass was also not affected. These findings in a marsupial suggest that the adjustment of thermoregulatory energy expenditure during the rest phase in accordance with energy availability is a phylogenetically old function of leptin.
瘦素在调节胎盘哺乳动物的体脂储备中发挥着重要作用，但能量消耗变化对这种调节的贡献仍存在争议。我们感兴趣的是，重组鼠瘦素会如何影响一种有袋类哺乳动物（粗尾袋鼩，体重25克）的代谢率（MR）和体温（Tb），这种有袋类动物已知会出现每日蛰伏现象，但缺乏具有产热活性的棕色脂肪组织。在一组八只动物中，在18摄氏度下禁食1天，瘦素治疗使蛰伏期的持续时间（体温Tb < 30摄氏度的时间）减半，并使每日平均最低体温Tb升高4.5摄氏度，最低代谢率提高2.2倍。因此，瘦素治疗使每日能量消耗增加了9%，尽管活动期的代谢率和体温并未升高。体重也未受影响。这些在有袋类动物中的发现表明，根据能量供应情况在休息期调节体温调节能量消耗是瘦素在系统发育上的一个古老功能。
