Cold adaptive thermogenesis in small mammals from different geographical zones of China

Citation
Qf. Li et al., Cold adaptive thermogenesis in small mammals from different geographical zones of China, COMP BIOC A, 129(4), 2001, pp. 949-961
Citations number
55
Language
INGLESE
art.tipo
Article
Categorie Soggetti
Animal Sciences",Physiology
Journal title
COMPARATIVE BIOCHEMISTRY AND PHYSIOLOGY A-MOLECULAR AND INTEGRATIVE PHYSIOLOGY
ISSN journal
1095-6433 → ACNP
Volume
129
Issue
4
Year of publication
2001
Pages
949 - 961
Database
ISI
SICI code
1095-6433(200107)129:4<949:CATISM>2.0.ZU;2-F
Abstract
The mechanisms of thermogenesis and thermoregulation were studied in the tr ee shrew (Tupaia belangeri) and greater vole (Eothenomys miletus) of the su btropical region, and Brandt's vole (Microtus brandti), Mongolian gerbil (M eriones unguiculatus), Daurian ground squirrel (Spermophilus dauricus) and plateau pika (Ochotona curzoniae) of the northern temperate zone. Resting m etabolic rate (RMR) and non-shivering thermogenesis (NST) increased signifi cantly in T. belangeri, E miletus, M. brandti and M. unguiculatus after col d acclimation (4 degreesC) for 4 weeks. In T. belangeri, the increase in RM R and thermogenesis at liver cellular level were responsible for enhancing the capacity of enduring cold stress, and homeothermia was simultaneously e xtended. Stable body temperature in M. brandti, E. miletus, M. unguiculatus and O. curzoniae was maintained mainly through increase in NST, brown adip ose tissue (BAT) mass and its mitochondrial protein content? and the upregu lation of uncoupling protein (UCP1) mRNA, as well as enhancement of the act ivity of cytochrome C oxidase, ol-glycerophosphate oxidase and T, 5 ' -deio denase in BAT mitochondria. The RMR in O. curzoniae and euthermic S. dauric us was not changed, while NST significantly increased during cold exposure; the former maintained their stable body temperature and mass, while body t emperature in the latter declined by 4.8 degreesC. The serum T-3 concentrat ion or ratio of T-3/T-4 in all the species was enhanced after cold acclimat ion. Results indicated that: (1) the adaptive mechanisms of T. belangeri re siding in the subtropical region to cold are primarily by increasing RMR an d secondly by increasing NST, and the mechanisms of thermogenesis are simil ar to those in tropical mammals; (2) in small mammals residing in northern regions, the adaptation to cold is chiefly to increase NST: (3) the mechani sm of cold-induced thermogenesis in E. miletus residing in subtropical and high mountain regions is similar to that in the north; (4) a low RMR in war m environments and peak RMR and NST in cold environments enabled M unguicul atus to tolerate a semi-desert climate; (5) O. curzoniae has unusually high RMR and high NST, acting mainly via increasing NST to adapt to extreme col d of the Qinghai-Tibet Plateau; (6) the adaptation of euthermic S. dauricus to cold is due to an increase in NST and a relaxed homeothermia; and lastl y (7) the thyroid hormone is involved in the regulation of cold adaptive th ermogenesis in all the species studied. (C) 2001 Elsevier Science Inc. All rights reserved.