Wittert Gary A, Turnbull Helen, Hope Perdita
Department of Medicine, University of Adelaide, Royal Adelaide Hospital, Adelaide, 5000, South Australia.
Physiol Behav. 2005 Aug 7;85(5):613-20. doi: 10.1016/j.physbeh.2005.06.012.
The adipose tissue derived cytokine leptin, modifies energy balance via effects on both food intake and energy expenditure. It is not clear, however, whether the component of energy expenditure accounted for by voluntary (nonexercise) physical activity is increased in response to leptin. The aim of this study was to investigate the effect of exogenously administered leptin on physical activity in the marsupial Sminthopsis crassicaudata. Body weight, tail width and food intake, were measured daily and physical activity was measured hourly in normal lean S. crassicaudata (n=8) with ad libitum access to standard laboratory diet. After 5 days baseline the animals were divided into two equal groups (n=4), and either human recombinant leptin (2.5 mg/kg) or placebo was administered twice daily intraperitoneally. Approximately 81% of the total daily activity during the baseline period occurred during the nocturnal phase. After 9 days of leptin administration, there were significant decreases in body weight (P<0.001) and fat content (P<0.01), which were not accompanied by a decrease in total energy intake. Overall daily physical activity increased (P=0.028); this effect was confined to the dark phase (P=0.033). We conclude that in lean S. crassicaudata the exogenous administration of human recombinant leptin results in a decrease in adiposity which occurs in the absence of a measurable effect on food intake and is associated with an increase in non-exercise physical activity at least over the duration of this study.
脂肪组织衍生的细胞因子瘦素通过对食物摄入和能量消耗的影响来调节能量平衡。然而，尚不清楚瘦素是否会使自愿（非运动）体力活动所消耗的能量成分增加。本研究的目的是调查外源性给予瘦素对有袋动物肥尾小袋鼬体力活动的影响。对正常瘦型的肥尾小袋鼬（n = 8）自由采食标准实验室日粮，每天测量体重、尾宽和食物摄入量，每小时测量体力活动。在5天的基线期后，将动物分成两组，每组4只，分别每天两次腹腔注射人重组瘦素（2.5 mg/kg）或安慰剂。基线期每日总活动量的约81%发生在夜间。给予瘦素9天后，体重（P<0.001）和脂肪含量（P<0.01）显著下降，而总能量摄入量并未减少。总体每日体力活动增加（P = 0.028）；这种影响仅限于黑暗期（P = 0.033）。我们得出结论，在瘦型肥尾小袋鼬中，外源性给予人重组瘦素会导致肥胖程度降低，这一过程在对食物摄入量无显著影响的情况下发生，并且至少在本研究期间与非运动体力活动增加有关。
