Bartness T J, Wade G N
Neurosci Biobehav Rev. 1985 Winter;9(4):599-612. doi: 10.1016/0149-7634(85)90006-5.
Syrian (Mesocricetus auratus) and Siberian (Phodopus sungorus sungorus) hamsters exhibit seasonal changes in body weight mainly by altering their carcass lipid stores. These seasonal changes are triggered largely by the photoperiod. Although both species exhibit gonadal regression when exposed to short photoperiods ("winterlike") daylength), they show opposite body weight changes. Syrian hamsters gain weight, but Siberian hamsters lose weight following short photoperiod exposure. Syrian hamsters prepare for overwintering by increasing energy stored as carcass lipid. In contrast, Siberian hamsters decrease their metabolic mass and therefore require lower energy intake for energy maintenance. In Syrian, and perhaps Siberian hamsters the short day-induced weight changes are exaggerated by high fat diets. Both species show photoperiod-induced changes in body weight without changing their food intake, suggesting a metabolic basis for these effects. In Syrian hamsters, the obesity is not secondary to gonadal regression, whereas in Siberian hamsters, the decrease in body weight is independent of the gonads for males but may be dependent upon the gonads in females. The pineal gland and its hormone, melatonin, are important transducers of photoperiodic signals in hamsters. This is certainly true for Siberian hamsters, in which pinealectomy blocks the short day-induced body weight loss. In contrast, pinealectomy has little effect on short day-induced weight gain in Syrian hamsters. Nevertheless, in both species, the body weight and gonadal changes induced by short day exposure are mimicked by systemic administration of melatonin in long day-housed animals. Thus, for these two hamster species, the same hormone, melatonin, produces opposite effects on body weight but does so by affecting the same carcass component. The target sites of action for the effects of melatonin on body weight change, energy metabolism, and reproductive status are not known. However, the suprachiasmatic and paraventricular nuclei of the hypothalamus are potentially important sites of action. The target site(s) and mechanism(s) of action for the pineal/melatonin-independent effect of photoperiod on body weight in Syrian hamsters are also unknown. This photoperiodic response is highly unusual among mammals in that it is not pineal-dependent. Studies of the mechanisms underlying these body weight changes in Syrian and Siberian hamsters may provide fundamental knowledge about how environmental influences affect obesity and they may also provide insight into the various strategies for overwintering shaped by natural selection.(ABSTRACT TRUNCATED AT 400 WORDS)
叙利亚仓鼠（金仓鼠）和西伯利亚仓鼠（黑线毛足鼠）主要通过改变其体脂储备来呈现体重的季节性变化。这些季节性变化很大程度上是由光周期触发的。尽管这两个物种在暴露于短光周期（“类似冬季”的日照长度）时都会出现性腺退化，但它们的体重变化却相反。叙利亚仓鼠体重增加，而西伯利亚仓鼠在短光周期暴露后体重减轻。叙利亚仓鼠通过增加作为体脂储存的能量来为越冬做准备。相比之下，西伯利亚仓鼠会减少其代谢质量，因此维持能量所需的能量摄入量较低。在叙利亚仓鼠中，或许在西伯利亚仓鼠中也是如此，高脂肪饮食会加剧短日照诱导的体重变化。这两个物种都表现出光周期诱导的体重变化，而食物摄入量不变，这表明这些影响存在代谢基础。在叙利亚仓鼠中，肥胖并非性腺退化的继发结果，而在西伯利亚仓鼠中，体重下降对雄性而言与性腺无关，但对雌性而言可能依赖于性腺。松果体及其激素褪黑素是仓鼠光周期信号的重要传导者。对于西伯利亚仓鼠来说肯定是这样，松果体切除会阻止短日照诱导的体重减轻。相比之下，松果体切除对叙利亚仓鼠短日照诱导的体重增加影响很小。然而，在这两个物种中，短日照暴露诱导的体重和性腺变化在长日照饲养的动物中通过全身性给予褪黑素得以模拟。因此，对于这两种仓鼠，相同的激素褪黑素对体重产生相反的影响，但却是通过影响相同的身体组成部分来实现的。褪黑素对体重变化、能量代谢和生殖状态影响的作用靶点尚不清楚。然而，下丘脑的视交叉上核和室旁核可能是重要的作用位点。光周期对叙利亚仓鼠体重的非松果体/褪黑素依赖性影响的作用靶点和作用机制也不清楚。这种光周期反应在哺乳动物中非常不寻常，因为它不依赖松果体。对叙利亚和西伯利亚仓鼠体重变化潜在机制的研究可能会提供关于环境影响如何导致肥胖的基础知识，并且还可能深入了解自然选择塑造的各种越冬策略。（摘要截断于400字）
