title: Neuroendocrine control of appetite in Atlantic halibut (Hippoglossus hippoglossus): changes during metamorphosis and effects of feeding.
abstract: Hormones and neuropeptides play a crucial role in the appetite control system of vertebrates, yet few studies have focused on their importance during early teleost development. In this study, we analysed the expression patterns of the appetite-controlling factors ghrelin, neuropeptide Y (NPY), peptide YY (PYY), pro-opiomelanocortin (POMC-C), and cocaine-amphetamine-related transcript (CART) by quantitative PCR. Transcript expression was investigated in response to feeding in developing Atlantic halibut larvae: before (premetamorphic stage 5) and during metamorphosis (stages 8 and 9B), and also in response to a fast-refeed challenge. We show that ghrelin transcript expression increased in synchrony with stomach development, while CART was significantly reduced during larval development. PYY was up-regulated 1 and 3 h after feeding in stage 5. Transcript abundance of other appetite-controlling factors did not change in response to feeding. Fasting-refeeding trials (majority of larvae in metamorphosing stage 7) revealed a down-regulation of POMC-C 30 min after refeeding, while ghrelin, PYY and NPY transcript expression increased 2, 4 and 5 h after refeeding, respectively. In summary, transcripts for key appetite-controlling factors were detected early during development in Atlantic halibut and their emergence was not correlated with metamorphosis, with the exception of ghrelin. Our results suggest that PYY may mediate satiety early in larval development. The differing response times of POMC-C, ghrelin, PYY and NPY to a meal are intriguing and require further exploration to understand the role of each player in appetite control.
authors.affiliation: Department of Biology, University of Bergen, PO Box 7803, Bergen NO-5020, Norway. Electronic address: Ana.Gomes@uib.no.
authors.forename: Ana S
authors.initials: AS
authors.lastname: Gomes
authors.affiliation: Department of Biology, University of Bergen, PO Box 7803, Bergen NO-5020, Norway.
authors.forename: Ann-Elise Olderbakk
authors.initials: AE
authors.lastname: Jordal
authors.affiliation: Department of Biology, University of Bergen, PO Box 7803, Bergen NO-5020, Norway.
authors.forename: Kjetil
authors.initials: K
authors.lastname: Olsen
authors.affiliation: Institute of Marine Research, Austevoll Aquaculture Research Station, Storebø NO-5392, Norway.
authors.forename: Torstein
authors.initials: T
authors.lastname: Harboe
authors.affiliation: Comparative and Molecular Endocrinology Group, Centre for Marine Sciences (CCMAR), University of Algarve, Campus de Gambelas, Faro 8005-139, Portugal.
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Power
authors.affiliation: Department of Biology, University of Bergen, PO Box 7803, Bergen NO-5020, Norway.
authors.forename: Ivar
authors.initials: I
authors.lastname: Rønnestad
mesh_terms: D000824:Animal Nutritional Physiological Phenomena / Q000502:physiology*; D000818:Animals; D001069:Appetite Regulation / Q000235:genetics / Q000502:physiology*; D004435:Eating; D005215:Fasting; D029941:Fish Proteins / Q000235:genetics; D005432:Flounder / Q000502:physiology*; D054439:Ghrelin / Q000235:genetics; D007814:Larva / Q000254:growth & development / Q000502:physiology; D008675:Metamorphosis, Biological / Q000502:physiology*; D008969:Molecular Sequence Data; D009419:Nerve Tissue Proteins / Q000235:genetics; D009478:Neuropeptide Y / Q000235:genetics; D009490:Neurosecretory Systems / Q000502:physiology*; D011333:Pro-Opiomelanocortin / Q000235:genetics; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein
chemical_list: D029941:Fish Proteins; D054439:Ghrelin; D009419:Nerve Tissue Proteins; D009478:Neuropeptide Y; D000098882:Cocaine- and Amphetamine-Regulated Transcript Protein; D011333:Pro-Opiomelanocortin
keywords: Appetite; Atlantic halibut; CART; Fast–refeed challenge; Ghrelin; NPY; Ontogeny; POMC-C; PYY