title: Fat pad-specific effects of lipectomy on foraging, food hoarding, and food intake.
abstract: Unlike most species, after food deprivation, Siberian hamsters increase foraging and food hoarding, two appetitive ingestive behaviors, but not food intake, a consummatory ingestive behavior. We previously demonstrated (Wood AD, Bartness TJ, Am J Physiol Regul Integr Comp Physiol 272: R783-R792, 1997) that increases in food hoarding are triggered by directly decreasing body fat levels through partial surgical lipectomy; however, we did not test if lipectomy affected foraging, nor if the magnitude of the lipid deficit affected food hoard size. Therefore, we tested whether varying the size of the lipectomy-induced lipid deficit and/or foraging effort affected foraging, food hoarding, or food intake. This was accomplished by housing adult male Siberian hamsters in a foraging/hoarding system and removing (x) both epididymal white adipose tissue (EWATx) pads, both inguinal white adipose tissue (IWATx) pads, or both EWAT and IWAT pads (EWATx + IWATx) and measuring foraging, food hoarding, and food intake for 12 wk. The lipectomy-induced lipid deficit triggered different patterns of white adipose tissue mass compensation that varied with foraging effort. Foraging for food (10 wheel revolutions to earn a food pellet) abolished the EWATx-induced compensation in IWAT pad mass. The magnitude of the lipid deficit did not engender a proportional change in any of the appetitive or consummatory ingestive behaviors. EWATx caused the greatest increase in food hoarding compared with IWATx or EWATx + IWATx, when animals were required to forage for their food. Collectively, it appears that the magnitude of a lipid deficit does not affect appetitive or consummatory behaviors; rather, when energy (foraging) demands are increased, loss of specific (gonadal) fat pads can preferentially stimulate increases in food hoarding.
authors.affiliation: Department of Biology, Georgia State University, 24 Peachtree Center Avenue NE, Atlanta, GA 30302-4010, USA.
authors.forename: Megan E
authors.initials: ME
authors.lastname: Dailey
authors.forename: Timothy J
authors.initials: TJ
authors.lastname: Bartness
mesh_terms: D052436:Adipose Tissue, White / Q000502:physiology* / Q000601:surgery; D000818:Animals; D001066:Appetite / Q000502:physiology*; D001823:Body Composition; D015992:Body Mass Index; D006224:Cricetinae; D004435:Eating / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology*; D020738:Leptin / Q000097:blood; D015187:Lipectomy; D008297:Male; D017111:Phodopus; D013739:Testosterone / Q000097:blood
chemical_list: D020738:Leptin; D013739:Testosterone