冬眠する哺乳類シリアンハムスターに学ぶ、冬眠可能な生体状態とは？

Hibernation is an adaptive strategy for surviving during periods with little or no food availability, by profoundly reducing the metabolic rate and the core body temperature (Tb). Mammalian hibernators store fat extensively in white adipose tissues (WATs) during pre-hibernation period to prepare for hibernation. Thus, they undergo adaptive body remodelling in autumn, the pre-hibernation period, prior to hibernation, whereas little is known about the physiological and molecular mechanisms of the pre-hibernation remodelling. Syrian hamsters (Mesocricetus auratus) are facultative hibernators that can hibernate irrespective of seasons when exposed to prolonged short photoperiod and cold ambient temperature (SD-Cold) conditions. We found that before the initiation of hibernation, the body mass of Syrian hamsters decreased below a threshold, indicating that hibernation in this species depends on body condition. Global profiling of gene expression in various tissues of animals during the pre-hibernation period and hibernation period identified adaptive changes for hibernation at molecular level. Thus, Syrian hamsters as a model animal to study hibernation provide us a unique and convenient opportunity to analyse molecular and physiological mechanisms of adaptive pre-hibernation remodelling under a laboratory condition.

特別講演要旨（Summary of Special Lecture）