title: VGF-derived peptide, TLQP-21, regulates food intake and body weight in Siberian hamsters.
abstract: The Siberian hamster survives winter by decreasing food intake and catabolizing abdominal fat reserves, resulting in a sustained, profound loss of body weight. VGF gene expression is photoperiodically regulated in the hypothalamus with significantly higher expression in lean Siberian hamsters. The aim of this study was to investigate the role of VGF in regulating these seasonal cycles by determining the effects of a VGF-derived peptide (TLQP-21) on food intake and body weight. Acute intracerebroventricular administration of TLQP-21 decreased food intake, and chronic treatment caused a sustained reduction in food intake and body weight and decreased abdominal fat depots. Behavioral analysis revealed that TLQP-21 reduced meal size but not the frequency of feeding bouts, suggesting a primary action on satiety. Hamsters treated with TLQP-21 lost a similar amount of weight as a pair-fed group in which food intake was matched to that of the TLQP-21-treated group. Central or peripheral treatment with TLQP-21 did not produce a significant effect on resting metabolic rate. We conclude that the primary action of TLQP-21 is to decrease food intake rather than increase energy expenditure. TLQP-21 treatment caused a decrease in UCP-1 mRNA in brown adipose tissue, but hypothalamic expression of orexigenic and anorexigenic neuropeptide genes remained unchanged after TLQP-21 treatment, although compensatory increases in NPY and AgRP mRNA were observed in the pair-fed hamsters. The effects of TLQP-21 administration are similar to those in hamsters in short days, suggesting that increased VGF activity may contribute to the hypophagia that underlies the seasonal catabolic state.
authors.affiliation: School of Biomedical Sciences and Institute of Neuroscience, University of Nottingham Medical School, Queen's Medical Centre, Nottingham NG7 2UH, United Kingdom. preeti.jethwa@nottingham.ac.uk
authors.forename: Preeti H
authors.initials: PH
authors.lastname: Jethwa
authors.forename: Amy
authors.initials: A
authors.lastname: Warner
authors.forename: Kanishka N
authors.initials: KN
authors.lastname: Nilaweera
authors.forename: John M
authors.initials: JM
authors.lastname: Brameld
authors.forename: John W
authors.initials: JW
authors.lastname: Keyte
authors.forename: Wayne G
authors.initials: WG
authors.lastname: Carter
authors.forename: Neil
authors.initials: N
authors.lastname: Bolton
authors.forename: Michael
authors.initials: M
authors.lastname: Bruggraber
authors.forename: Peter J
authors.initials: PJ
authors.lastname: Morgan
authors.forename: Perry
authors.initials: P
authors.lastname: Barrett
authors.forename: Francis J P
authors.initials: FJ
authors.lastname: Ebling
mesh_terms: D000818:Animals; D001835:Body Weight / Q000187:drug effects / Q000502:physiology*; D006224:Cricetinae; D004435:Eating / Q000187:drug effects / Q000502:physiology*; D004734:Energy Metabolism / Q000187:drug effects / Q000502:physiology; D005247:Feeding Behavior / Q000187:drug effects / Q000502:physiology; D007031:Hypothalamus / Q000502:physiology; D007276:Injections, Intraventricular; D008297:Male; D009479:Neuropeptides / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D009929:Organ Size; D010101:Oxygen Consumption / Q000187:drug effects / Q000502:physiology; D010446:Peptide Fragments / Q000138:chemical synthesis / Q000378:metabolism* / Q000494:pharmacology; D017111:Phodopus
chemical_list: D009479:Neuropeptides; D010446:Peptide Fragments; C522412:TLQP-21 peptide; C522413:VGF peptide