title: Seasonal changes of body mass and energy budget in striped hamsters: the role of leptin.
abstract: Proper adjustments of physiology and behavior are required for small mammals to cope with seasonal climate change. The aim of this study was to examine the role of leptin in the regulation of body mass and energy budget in striped hamsters. We first investigated seasonal changes in body mass, energy budget, and serum leptin levels in hamsters acclimated to outdoor natural daylight and ambient temperature. Then we assessed the effect of leptin administration on energy budget, serum lipoprotein lipase (LPL) and hepatic lipase (HL) activities, and gene expression of uncoupling protein 1 (UCP1) in brown adipose tissue and of hypothalamic neuropeptides associated with the regulation of energy balance in hamsters maintained at 21° and 5°C. Hamsters showed constant body mass throughout the four seasons but significantly increased food intake and thermogenesis in winter, compared to summer. Minimum body fat was observed in winter, and minimum serum leptin was found in autumn. Hamsters housed at 5°C showed higher energy intake, upregulated gene expression of UCP1 and hormone-sensitive lipase, and lower fat content and LPL and HL activity than the animals maintained at 21°C. Leptin administration had no effect on energy intake but increased maximal thermogenic capacity, as indicated by upregulated UCP1 gene expression at both 21° and 5°C. Body fat and activity of LPL and HL were decreased in hamsters treated with leptin. The results suggest that leptin plays an important role in the seasonal regulation of thermogenic capacity and body composition in striped hamsters. Leptin may be involved in increasing maximal thermogenesis in the cold rather than acting as a starvation signal to increase energy intake.
authors.affiliation: School of Life and Environmental Science, Wenzhou University, Wenzhou 325027, China; 2State Key Laboratory of Integrated Management for Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, Beijing 100101, China; 3School of Agricultural Science, Liaocheng University, Liaocheng, Shandong 252059, China.
authors.forename: Zhi-Jun
authors.initials: ZJ
authors.lastname: Zhao
authors.forename: Qing-sheng
authors.initials: QS
authors.lastname: Chi
authors.forename: Jing
authors.initials: J
authors.lastname: Cao
authors.forename: De-Hua
authors.initials: DH
authors.lastname: Wang
mesh_terms: D000064:Acclimatization; D000273:Adipose Tissue; D050154:Adiposity; D000818:Animals; D001835:Body Weight; D003412:Cricetulus / Q000502:physiology*; D002149:Energy Intake; D004734:Energy Metabolism; D005786:Gene Expression Regulation; D007473:Ion Channels / Q000235:genetics / Q000378:metabolism; D020738:Leptin / Q000097:blood / Q000378:metabolism*; D008049:Lipase / Q000378:metabolism; D008071:Lipoprotein Lipase / Q000378:metabolism; D008297:Male; D024101:Mitochondrial Proteins / Q000235:genetics / Q000378:metabolism; D009479:Neuropeptides / Q000235:genetics / Q000378:metabolism; D012621:Seasons; D002787:Sterol Esterase / Q000235:genetics / Q000378:metabolism; D000071256:Uncoupling Protein 1
chemical_list: D007473:Ion Channels; D020738:Leptin; D024101:Mitochondrial Proteins; D009479:Neuropeptides; D000071256:Uncoupling Protein 1; D002787:Sterol Esterase; D008049:Lipase; D008071:Lipoprotein Lipase