LeBlanc J, Labrie A
J Appl Physiol Respir Environ Exerc Physiol. 1981 Dec;51(6):1428-32. doi: 10.1152/jappl.1981.51.6.1428.
Exposure to moderate cold for a few weeks causes adaptation through the development of nonshivering thermogenesis primarily in the brown adipose tissue. Exposure to severe cold by repeated short exposures also causes adaptation but by mechanisms that seem to be different. These latter results were confirmed in mice. It was also found that this type of adaptation is nonspecific because it can be produced by other stresses such as swimming or fasting. Simultaneous determinations of glycogen in the liver and soleus and tibialis muscles indicated a possible role for this substrate in cold resistance. Repeated cold exposure (8 times at -15 degrees C for 10 min), swimming for 3 h, or fasting for 48 h--all reduced the glycogen stores when measured immediately after the stress. However, the levels of glycogen were significantly increased above the initial values (P less than 0.01) when the determinations were made 24 h later. Cold tolerance measured by resistance to hypothermia at -5 degrees C was improved only when the test was done 24 h after the stress had taken place. Thus, cold resistance, as described in this study, is nonspecific and our results suggest that glycogen stores could serve as a rate-limiting substrate.
几周的适度寒冷暴露会通过主要在棕色脂肪组织中发展非颤抖性产热来引起适应。通过反复短时间暴露于严寒也会引起适应，但机制似乎有所不同。后一种结果在小鼠中得到了证实。还发现这种适应类型是非特异性的，因为它可以由其他应激因素如游泳或禁食引起。同时测定肝脏、比目鱼肌和胫骨前肌中的糖原表明该底物在耐寒性中可能发挥作用。反复冷暴露（在-15℃下8次，每次10分钟）、游泳3小时或禁食48小时——在应激后立即测量时，所有这些都会减少糖原储备。然而，在24小时后进行测定时，糖原水平显著高于初始值（P<0.01）。仅在应激发生24小时后进行测试时，通过在-5℃下对体温过低的抵抗力来衡量的耐寒性才会提高。因此，如本研究中所述，耐寒性是非特异性的，我们的结果表明糖原储备可能作为一种限速底物。
