Nieminen Petteri, Saarela Seppo, Pyykönen Teija, Asikainen Juha, Mononen Jaakko, Mustonen Anne-Mari
Department of Biology, University of Joensuu, FIN-80101, Joensuu, Finland.
J Exp Zool A Comp Exp Biol. 2004 Dec 1;301(12):919-29. doi: 10.1002/jez.a.126.
The raccoon dog (Nyctereutes procyonoides) is an omnivorous canid utilizing the passive wintering strategy in the boreal climate. Farmed raccoon dogs (n=12) were randomly assigned into two study groups on 26 November 2003. Between 3 December 2003 and 27 January 2004, half of the animals were fasted for 8 weeks and plasma weight-regulatory hormone concentrations determined on 26 November and 30 December 2003 and on 27 January 2004. The plasma peptide YY, ghrelin, and growth hormone (GH) concentrations increased due to food deprivation, while the T4 and Acrp30 concentrations decreased. Furthermore, the plasma GH concentrations were higher in the fasted raccoon dogs than in the fed animals, which had higher plasma insulin, glucagon, and T4 concentrations. However, fasting had no effect on the plasma leptin concentrations. The results confirm previous findings with unchanged leptin levels in fasting carnivores. Increased GH levels probably contribute to increased lipolysis and mobilization of fat stores. Ghrelin can also enhance lipolysis by increasing the GH levels. The decreased levels of T4 may reduce the metabolic rate. The plasma dopamine concentrations decreased due to fasting unlike observed previously in rats. Together with the unaffected adrenaline, noradrenaline, and cortisol concentrations, this suggests that food deprivation in winter does not cause stress to the raccoon dog but is an integral part of its natural life history.
貉（Nyctereutes procyonoides）是一种杂食性犬科动物，在寒带气候中采用被动越冬策略。2003年11月26日，将12只养殖貉随机分为两个研究组。在2003年12月3日至2004年1月27日期间，一半的动物禁食8周，并于2003年11月26日、12月30日和2004年1月27日测定血浆体重调节激素浓度。由于食物缺乏，血浆肽YY、胃饥饿素和生长激素（GH）浓度升高，而甲状腺素（T4）和Acrp30浓度降低。此外，禁食貉的血浆GH浓度高于喂食动物，喂食动物的血浆胰岛素、胰高血糖素和T4浓度较高。然而，禁食对血浆瘦素浓度没有影响。这些结果证实了之前关于禁食食肉动物瘦素水平不变的研究结果。GH水平升高可能有助于增加脂肪分解和脂肪储备的动员。胃饥饿素也可以通过提高GH水平来增强脂肪分解。T4水平降低可能会降低代谢率。与之前在大鼠中观察到的情况不同，禁食导致血浆多巴胺浓度降低。与未受影响的肾上腺素、去甲肾上腺素和皮质醇浓度一起，这表明冬季食物缺乏不会给貉带来压力，而是其自然生活史的一个组成部分。
