title: Leptin regulates energy intake but fails to facilitate hibernation in fattening Daurian ground squirrels (Spermophilus dauricus).
abstract: Body fat storage before hibernation affects the timing of immergence in Daurian ground squirrels (Spermophilus dauricus). Leptin is an adipose signal and plays vital role in energy homeostasis mainly by action in brain. To test the hypothesis that leptin plays a role in facilitating the process of hibernation, squirrels were administrated with recombinant murine leptin (1μg/day) through intracerebroventricular (ICV) injection for 12 days during fattening. From day 7 to 12, animals were moved into a cold room (5±1°C) with constant darkness which functioned as hibernaculum. Energy intake, body mass and core body temperature (Tb) were continuously monitored throughout the course of experiment. Resting metabolic rate (RMR) was measured under both warm and cold conditions. At the end of leptin administration, we measured the serum concentration of hormones related to energy regulation, mRNA expression of hypothalamic neuropeptides and uncoupling protein 1 (UCP1) levels in brown adipose tissue (BAT). Our results showed that during leptin administration, the cumulative food intake and increase of body mass were suppressed while Tb and RMR were unaltered. The proportion of torpid squirrels was not different between two groups. At the end of leptin administration, the expressions of hypothalamic neuropeptide Y and agouti gene-related protein were suppressed. There were no differences in UCP1 mRNA expression or protein content in BAT between groups. Our data suggest that leptin can affect energy intake via hypothalamic neuropeptides, but is not involved in the initiation of hibernation in fattening Daurian ground squirrels.
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang, Beijing 100101, China; University of Chinese Academy of Sciences, Beijing 100049, China.
authors.forename: Xin
authors.initials: X
authors.lastname: Xing
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang, Beijing 100101, China.
authors.forename: Gang-Bin
authors.initials: GB
authors.lastname: Tang
authors.affiliation: College of Life Science, Shenyang Normal University, 253 Huanghe North Street, Shenyang 110034, China.
authors.forename: Ming-Yue
authors.initials: MY
authors.lastname: Sun
authors.affiliation: College of Life Science, Shenyang Normal University, 253 Huanghe North Street, Shenyang 110034, China.
authors.forename: Chao
authors.initials: C
authors.lastname: Yu
authors.affiliation: College of Life Science, Shenyang Normal University, 253 Huanghe North Street, Shenyang 110034, China.
authors.forename: Shi-Yi
authors.initials: SY
authors.lastname: Song
authors.affiliation: College of Life Science, Shenyang Normal University, 253 Huanghe North Street, Shenyang 110034, China.
authors.forename: Xin-Yu
authors.initials: XY
authors.lastname: Liu
authors.affiliation: College of Life Science, Shenyang Normal University, 253 Huanghe North Street, Shenyang 110034, China. Electronic address: yangming@synu.edu.cn.
authors.forename: Ming
authors.initials: M
authors.lastname: Yang
authors.affiliation: State Key Laboratory of Integrated Management of Pest Insects and Rodents, Institute of Zoology, Chinese Academy of Sciences, 1 Beichen West Road, Chaoyang, Beijing 100101, China. Electronic address: wangdh@ioz.ac.cn.
authors.forename: De-Hua
authors.initials: DH
authors.lastname: Wang
mesh_terms: D002001:Adipose Tissue, Brown / Q000187:drug effects / Q000378:metabolism / Q000502:physiology; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002149:Energy Intake; D006605:Hibernation / Q000187:drug effects*; D006963:Hyperphagia / Q000378:metabolism; D007031:Hypothalamus / Q000187:drug effects / Q000378:metabolism; D020738:Leptin / Q000494:pharmacology*; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism; D012589:Sciuridae / Q000378:metabolism / Q000502:physiology*; D022722:Thermogenesis; D000071256:Uncoupling Protein 1 / Q000235:genetics / Q000378:metabolism
chemical_list: D020738:Leptin; D009478:Neuropeptide Y; D000071256:Uncoupling Protein 1
keywords: Daurian ground squirrels (Spermophilus dauricus); Fattening; Hibernation; Leptin