Thermoregulation in hibernating mammals: The role of the "thyroid hormones system".
Thermoregulation in hibernating mammals: The role of the "thyroid hormones system".
复制标题
冬眠哺乳动物中的温度调节：“甲状腺激素系统”的作用。
DOI：
10.1016/j.mce.2020.111054
复制
发表时间：
2021-01-01
影响因子：
4.1
通讯作者：
Drew KL
中科院分区：
文献类型：
--
作者：
Frare C;Williams CT;Drew KL
冬眠是一种独特的进化适应，以保存能量。在冬眠前（即秋季）季节，核心体温的逐步下降和新陈代谢的进一步减少是体温调节的季节性调节的基础。冬眠的开始需要体温调节属性的显著变化，包括体温的调整和产热能力的组织特异性增加。冬眠季节的特点是产热的调节性抑制，允许休眠的开始被产热的周期性激活中断，以维持间歇觉醒。已知甲状腺激素调节体温和新陈代谢，因此，下丘脑-垂体-甲状腺轴和甲状腺激素已被研究为冬眠现象中产热的调节剂，但其机制仍知之甚少。在这篇综述中，我们提出了一个概述什么是已知的甲状腺激素在冬眠物种的产热作用跨季节和冬眠季节（torpor-interbout觉醒周期）。总体而言，下丘脑-垂体-甲状腺轴和甲状腺激素在冬眠前季节发挥作用，以提高产热能力。在冬眠期间，产热在中缝苍白核内的交感运动前神经元水平和下丘脑中的脱碘酶表达被减弱。此外，由于最近的工作突出了甲状腺激素在中枢神经系统中激活产热的直接作用，我们推测在冬眠物种中可能发生类似的机制来调节跨季节的产热和维持interbout觉醒。然而，还需要进一步的实验来阐明甲状腺激素在冬眠中的作用，以了解甲状腺激素的代谢，运输和组织内的可用性可能是甲状腺状态最有说服力的指标。
Hibernation is a unique evolutionary adaptation to conserve energy. During the pre-hibernation (i.e. fall) season, a progressive decline in core body temperature and further decrease in metabolism underlie a seasonal modulation in thermoregulation. The onset of hibernation requires marked changes in thermoregulatory attributes including adjustment in body temperature and tissue specific increases in thermogenic capacity. The hibernation season is characterized by a regulated suppression in thermogenesis allowing the onset of torpor interrupted by periodic activation of thermogenesis to sustain interbout arousals. Thyroid hormones are known to regulate both body temperature and metabolism, and for this reason, the hypothalamic-pituitary-thyroid axis and thyroid hormones have been investigated as modulators of thermogenesis in the phenomenon of hibernation, but the mechanisms remain poorly understood. In this review, we present an overview of what is known about the thermogenic roles of thyroid hormones in hibernating species across seasons and within the hibernating season (torpor-interbout arousal cycle). Overall, the hypothalamic-pituitary-thyroid axis and thyroid hormones play a role in the pre-hibernation season to enhance thermogenic capacity. During hibernation, thermogenesis is attenuated at the level of sympathetic premotor neurons within the raphe pallidus and by deiodinase expression in the hypothalamus. Further, as recent work highlights the direct effect of thyroid hormones within the central nervous system in activating thermogenesis, we speculate how similar mechanisms may occur in hibernating species to modulate thermogenesis across seasons and to sustain interbout arousals. However, further experiments are needed to elucidate the role of thyroid hormones in hibernation, moving towards the understanding that thyroid hormones metabolism, transport and availability within tissues may be the most telling indicator of thyroid status.