title: Fasting levels of ghrelin covary with the brain response to food pictures.
abstract: Ghrelin figures prominently in the regulation of appetite in normal-weighed individuals. The apparent failure of this mechanism in eating disorders and the connection to addictive behavior in general demand a deeper understanding of the endogenous central-nervous processes related to ghrelin. Thus, we investigated processing of pictures showing palatable food after overnight fasting and following a standardized caloric intake (i.e. a 75-g oral glucose tolerance test) using functional magnetic resonance imaging and correlated it with blood plasma levels of ghrelin. Twenty-six healthy female and male volunteers viewed food and control pictures in a block design and rated their appetite after each block. Fasting levels of ghrelin correlated positively with food-cue reactivity in a bilateral network of visual processing-, reward- and taste-related regions, including limbic and paralimbic regions. Notably, among those regions were the hypothalamus and the midbrain where ghrelin receptors are densely concentrated. In addition, high fasting ghrelin levels were associated with stronger increases of subjective appetite during the food-cue-reactivity task. In conclusion, brain activation and subjective appetite ratings suggest that ghrelin elevates the hedonic effects of food pictures. Thereby, fasting ghrelin levels may generally enhance subjective craving when confronted with reward cues.
authors.affiliation: Department of Psychiatry and Psychotherapy, Technische Universität Dresden, Germany.
authors.forename: Nils B
authors.initials: NB
authors.lastname: Kroemer
authors.forename: Lena
authors.initials: L
authors.lastname: Krebs
authors.forename: Andrea
authors.initials: A
authors.lastname: Kobiella
authors.forename: Oliver
authors.initials: O
authors.lastname: Grimm
authors.forename: Maximilian
authors.initials: M
authors.lastname: Pilhatsch
authors.forename: Martin
authors.initials: M
authors.lastname: Bidlingmaier
authors.forename: Ulrich S
authors.initials: US
authors.lastname: Zimmermann
authors.forename: Michael N
authors.initials: MN
authors.lastname: Smolka
mesh_terms: D000328:Adult; D000818:Animals; D001066:Appetite / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D003463:Cues; D005215:Fasting / Q000097:blood; D005260:Female; D005502:Food; D059907:Functional Neuroimaging / Q000379:methods; D054439:Ghrelin / Q000097:blood* / Q000502:physiology; D005951:Glucose Tolerance Test; D006801:Humans; D006815:Hunger / Q000502:physiology*; D007091:Image Processing, Computer-Assisted; D008279:Magnetic Resonance Imaging; D008297:Male; D010775:Photic Stimulation / Q000379:methods; D012201:Reward; D012377:Rodentia; D013223:Statistics as Topic; D013997:Time Factors; D055815:Young Adult
chemical_list: D054439:Ghrelin