Raison J K, Augee M L, Aloia R C
CSIRO Division of Food Research and School of Biological Sciences, Macquarie University, North Ryde, New South Wales, Australia.
Am J Physiol. 1988 Mar;254(3 Pt 1):E378-83. doi: 10.1152/ajpendo.1988.254.3.E378.
Critical temperatures (T) for transitions in both lipid structure and enzyme function of mitochondrial membranes from liver, kidney, brown fat, and heart tissues were determined for the hibernator Spermophilus lateralis at two weekly intervals from early summer to late autumn and during hibernation. For all tissues T fell into one of three groups: those below 4 degrees C (the minimal level of accurate determination), those centered about a mean of 11.9 +/- 1.4 degrees C, and those centered about a mean of 20.9 +/- 1.8 degrees C. The T for tissues from torpid animals and from heart, at all sampling periods, was below 4 degrees C. For liver, kidney, and brown fat the mean T was approximately 21 degrees C in early summer but was lowered later in the season in a two-step process, falling to below 4 degrees C before the animals were exposed to cold and entering torpor. It is concluded that for mitochondria the thermal response of the membrane lipids is altered such that the transition in structure and function is always below the minimum body temperature likely to be experienced by this animal. Heart tissue is exceptional in that the transition is at a temperature consistent with a body temperature of torpor even in summer-active animals.
在从初夏到晚秋以及冬眠期间，每隔两周测定一次冬眠动物侧纹黄鼠肝脏、肾脏、褐色脂肪和心脏组织线粒体膜脂质结构和酶功能转变的临界温度（T）。对于所有组织，T分为三组之一：低于4摄氏度（精确测定的最低水平）、以11.9±1.4摄氏度为中心以及以20.9±1.8摄氏度为中心。在所有采样期，来自蛰伏动物和心脏组织的T低于4摄氏度。对于肝脏、肾脏和褐色脂肪，初夏时平均T约为21摄氏度，但在季节后期以两步过程降低，在动物暴露于寒冷并进入蛰伏之前降至4摄氏度以下。得出的结论是，对于线粒体，膜脂质的热反应发生了改变，使得结构和功能的转变始终低于该动物可能经历的最低体温。心脏组织是例外，即使在夏季活跃的动物中，其转变温度也与蛰伏体温一致。
