Department of Biology, Colorado State University, Fort Collins, CO, USA.
Comp Biochem Physiol A Mol Integr Physiol. 2011 Jul;159(3):322-31. doi: 10.1016/j.cbpa.2011.03.026. Epub 2011 Apr 5.
AMP-activated protein kinase (AMPK) is a cellular energy sensor that responds to low endogenous energy by stimulating fatty acid oxidation (through inactivation of acetyl-CoA carboxylase (ACC)) and food intake. Fasting generally stimulates phosphorylation of AMPK (pAMPK) and ACC (pACC), but it is unclear how AMPK and ACC react to a long-term fast (i.e. hibernation). We performed Western blots for total and pAMPK and pACC on tissues from a species of hibernator (Callospermophilus lateralis) after short-term summer fasting (1-5 days) and long-term winter fasting (3 months). Winter animals were sacrificed during hibernation at low body temperature (torpid, T(b)5°C) or at normal high T(b)(euthermic, T(b)37°C). We found a general increase in pAMPK in most tissues (liver, muscle, and white adipose tissue (WAT), but not hypothalamus) and pACC in all tissues after a short-term summer fast. Response of AMPK and ACC to a long-term winter fast differed by tissue-in liver, there was no difference in total or pAMPK or pACC between groups, but in muscle, WAT and BAT, euthermic GMGS had lower relative abundance of pAMPK and pACC than torpid animals. Therefore, AMPK may be an important energy sensor at all points in hibernator's circannual cycles of food intake and T(b).
腺苷酸活化蛋白激酶（AMPK）是一种细胞能量传感器，通过激活脂肪酸氧化（通过乙酰辅酶 A 羧化酶（ACC）失活）和食物摄入来响应低内源性能量。禁食通常会刺激 AMPK（pAMPK）和 ACC（pACC）的磷酸化，但尚不清楚 AMPK 和 ACC 对长期禁食（即冬眠）的反应如何。我们对一种冬眠物种（Callospermophilus lateralis）的组织进行了总 AMPK 和 pAMPK 以及 pACC 的 Western blot 分析，这些组织取自短期夏季禁食（1-5 天）和长期冬季禁食（3 个月）的动物。冬季动物在低温（休眠，T(b)5°C）或正常高温（euthermic，T(b)37°C）下冬眠时被处死。我们发现，在短期夏季禁食后，大多数组织（肝脏、肌肉和白色脂肪组织（WAT），但下丘脑除外）中的 pAMPK 普遍增加，所有组织中的 pACC 都增加。AMPK 和 ACC 对长期冬季禁食的反应因组织而异——在肝脏中，各组之间的总 AMPK 或 pAMPK 或 pACC 没有差异，但在肌肉、WAT 和 BAT 中，正常体温的 GMGS 动物的 pAMPK 和 pACC 的相对丰度低于休眠动物。因此，AMPK 可能是冬眠者食物摄入和 T(b)的年循环中的所有能量传感器。
