title: Intermittent cold exposure results in visceral adipose tissue "browning" in the plateau pika (Ochotona curzoniae).
abstract: The plateau pika has developed tolerance to cold and hypoxia in order to adapt to living in the extreme environment of the Qinghai-Tibetan Plateau. One mammalian mechanism for cold adaptation is thermogenesis by brown adipose tissue (BAT), but the degree to which pika exploits this mechanism or how it may be modified by the additional stresses of high altitude is not known. Intermittent Cold Exposure (ICE) is an approachable method to study cold adaptation in rodents. To investigate the role of adipose tissue in the adaptation of pika to cold temperatures, we have studied pika during ICE. We find that pika kept in warm temperatures has little classical brown fat, but "browning" of white adipose tissues is observed rapidly upon cold exposure. This is demonstrated by the increased expression of several markers of brown fat differentiation including uncoupling protein 1 (UCP-1). Surprisingly, this occurs mainly in visceral rather than epididymal adipose tissue. In addition, ICE increases the expression of several general adipose differentiation markers at both the mRNA and protein levels. These substantial changes in the distribution of fat are accomplished without changes in weight or blood levels of glucose and triglycerides, suggesting that the adaptable changes are coordinated and self-compensated. Together, our results demonstrate that ICE promotes recruitment of BAT in pika, and unlike small mammals in at lower altitudes, pika can activate visceral WAT to adapt to cold stress without major changes overall energy balance.
authors: Qinghai-Utah Joint Research Key lab for High Altitude Medicine, Qinghai University Medical School, 810001 Qinghai, Xining, PR China.
authors: Zhenzhong
authors: Z
authors: Bai
authors: Qinghai-Utah Joint Research Key lab for High Altitude Medicine, Qinghai University Medical School, 810001 Qinghai, Xining, PR China.
authors: Tana
authors: T
authors: Wuren
authors: Qinghai-Utah Joint Research Key lab for High Altitude Medicine, Qinghai University Medical School, 810001 Qinghai, Xining, PR China.
authors: Shou
authors: S
authors: Liu
authors: Qinghai-Utah Joint Research Key lab for High Altitude Medicine, Qinghai University Medical School, 810001 Qinghai, Xining, PR China.
authors: Shirui
authors: S
authors: Han
authors: Qinghai-Utah Joint Research Key lab for High Altitude Medicine, Qinghai University Medical School, 810001 Qinghai, Xining, PR China.
authors: Lin
authors: L
authors: Chen
authors: Department of Internal Medicine, University of Utah School of Medicine, Salt Lake City, UT, USA.
authors: Donald
authors: D
authors: McClain
authors: Qinghai-Utah Joint Research Key lab for High Altitude Medicine, Qinghai University Medical School, 810001 Qinghai, Xining, PR China. Electronic address: geriligao@hotmail.com.
authors: Ri-Li
authors: RL
authors: Ge
mesh_terms: D000818:Animals; D003080:Cold Temperature; D050152:Intra-Abdominal Fat / Q000502:physiology*; D007793:Lagomorpha
keywords: Adaptation; Browning; Intermitted cold exposure; Plateau pika; Visceral fat; White adipose tissues