Abstract
Mammalian hibernation is a strategy to survive during harsh winter with severe hypothermia and immobility
state. It has attracted many researchers for a long time but still remains to be elucidated. Studies in obligate
hibernators such as ground squirrels, chipmunk, and bears have revealed that they undergo systemic body
remodeling in a season-dependent manner prior to hibernation. By contrast, a facultative hibernator, Syrian
hamster, can hibernate in an environment-dependent manner; when they are exposed cold and short
photoperiod condition for several months, they begin to hibernate. This inducible hibernation allows
researchers to study mechanisms and significance of hibernation under a laboratory condition, whereas exact
nature of systemic body remodeling for hibernation in Syrian hamsters remain unclear yet. Using histology
and exhaustive gene expression analyses, we compared summer-like hamsters and winter-like hamsters and
found that Syrian hamsters extensively remodel white adipose tissues during a pre-hibernation period.
Particularly, simultaneous up-regulation of gene expression in both lipid catabolisms and lipid anabolisms
takes place in winter-like hamsters, which is a unique property of Syrian hamsters, a“food-storing”
hibernator who ingests food stored in the nest during hibernation season.
