Asikainen Juha, Mustonen Anne-Mari, Hyvärinen Heikki, Nieminen Petteri
University of Joensuu, Department of Biology, Joensuu, Finland.
J Exp Zool A Comp Exp Biol. 2003 Oct 1;299(2):180-7. doi: 10.1002/jez.a.10299.
The raccoon dog (Nyctereutes procyonoides, Canidae, Carnivora) is a middle-sized omnivore with excessive autumnal fattening and winter sleep. We studied adaptations of the species to boreal climate and photoperiod by following the plasma reproductive and thyroid hormone concentrations of farm-bred raccoon dogs (n=32) for 12 months. On August 16, 2000, and February 8, 2001, half of the raccoon dogs received continuous-release melatonin implants (the MEL group). The other half was sham-operated (the SHAM group). Between November 27, 2000, and January 25, 2001, half of the animals of both groups were fasted. The plasma testosterone concentrations of the MEL males peaked in February, a month earlier than in the SHAM males. Autumnal melatonin treatment also advanced the gestation period reflected by the plasma progesterone concentrations by seven weeks. Food deprivation in winter seems to accentuate the sex steroid response during the mating as the fasted males had higher testosterone concentrations than the fed males in February and March.
貉（Nyctereutes procyonoides，犬科，食肉目）是一种中型杂食动物，秋季过度育肥并冬眠。我们通过跟踪32只养殖貉12个月的血浆生殖激素和甲状腺激素浓度，研究了该物种对北方气候和光周期的适应性。2000年8月16日和2001年2月8日，一半的貉接受了褪黑素缓释植入物（MEL组）。另一半进行了假手术（SHAM组）。2000年11月27日至2001年1月25日，两组动物各有一半被禁食。MEL组雄性的血浆睾酮浓度在2月达到峰值，比SHAM组雄性早一个月。秋季褪黑素处理还使血浆孕酮浓度反映的妊娠期提前了7周。冬季食物剥夺似乎会增强交配期间的性类固醇反应，因为2月和3月禁食雄性的睾酮浓度高于喂食雄性。
