title: Diet-induced obesity attenuates fasting-induced hyperphagia.
abstract: Obesity impairs arcuate (ARC) neuropeptide Y (NPY)/agouti-releated peptide (AgRP) neuronal function and renders these homeostatic neurones unresponsive to the orexigenic hormone ghrelin. In the present study, we investigated the effect of diet-induced obesity (DIO) on feeding behaviour, ARC neuronal activation and mRNA expression following another orexigenic stimulus, an overnight fast. We show that 9 weeks of high-fat feeding attenuates fasting-induced hyperphagia by suppressing ARC neuronal activation and hypothalamic NPY/AgRP mRNA expression. Thus, the lack of appropriate feeding responses in DIO mice to a fast is caused by failure ARC neurones to recognise and/or respond to orexigenic cues. We propose that fasting-induced hyperphagia is regulated not by homeostatic control of appetite in DIO mice, but rather by changes in the reward circuitry.
authors.affiliation: Department of Physiology, Monash University, Clayton, Victoria, Australia.
authors.forename: D I
authors.initials: DI
authors.lastname: Briggs
authors.forename: M B
authors.initials: MB
authors.lastname: Lemus
authors.forename: E
authors.initials: E
authors.lastname: Kua
authors.forename: Z B
authors.initials: ZB
authors.lastname: Andrews
mesh_terms: D054369:Agouti-Related Protein / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001111:Arcuate Nucleus of Hypothalamus / Q000378:metabolism; D004032:Diet / Q000009:adverse effects*; D004036:Diet, Atherogenic; D015536:Down-Regulation; D005215:Fasting / Q000502:physiology*; D005247:Feeding Behavior / Q000502:physiology; D006963:Hyperphagia / Q000150:complications / Q000209:etiology* / Q000235:genetics / Q000378:metabolism; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D008820:Mice, Obese; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism; D009765:Obesity / Q000150:complications / Q000209:etiology* / Q000378:metabolism / Q000503:physiopathology*
chemical_list: D054369:Agouti-Related Protein; D009478:Neuropeptide Y