Adaptive thermogenesis of the liver in a tree shrew (Tupaia belangeri) during cold acclimation

Environmental cues play important roles in the regulation of an animal's physiology and behavior. The purpose of the present study was to test the hypothesis that ambient temperature was a cue to induce adjustments in body mass, energy intake and thermogenic capacity, associated with the role of the liver for adaptive thermogenesis in tree shrews (Tupaia belangeri), a unique species of small mammals in the Oriental realm. Many targets were measured, such as the state 3 and the state 4 of mitochondrial respiration, the protein content of mitochondria of the liver in T. belangeri under prolonged cold acclimation (5 +/- 1 degrees C, 12L : 12D light cycle) during different times [0 d (control), 7 d, 14 d, 21 d, 28 d]. We found the total protein, mitochondrial protein, and the state 3 and the state 4 of mitochondrial respiration of the liver greatly increased by 39.9%, 39.3%, 84.9% and 181.1% after 28 d in T. belangeri when exposed to cold, as compared with the controls, respectively. Thus, the liver plays a key role in the adaptive thermogenesis during cold acclimation in tree shrews; we believed that evidence from the physiological ecology is equally supportive of the island origin of tree shrews, T. belangeri. (C) Koninklijke Brill NV, Leiden, 2011.