title: Molecular, cellular and physiological evidences for the anorexigenic actions of nesfatin-1 in goldfish.
abstract: BACKGROUND
  Nesfatin-1 is a recently discovered anorexigen encoded in the precursor peptide, nucleobindin-2 (NUCB2) in mammals. To date, nesfatin-1 has not been described in any non-mammalian species, although some information is available in the sequenced genomes of several species. Our objective was to characterize nesfatin-1 in fish.
  
  
  RESULTS
  In the present study, we employed molecular, immunohistochemical, and physiological studies to characterize the structure, distribution, and appetite regulatory effects of nesfatin-1 in a non-mammalian vertebrate. A very high conservation in NUCB2 sequences, especially in the nesfatin-1 region was found in lower vertebrates. Abundant expression of NUCB2 mRNA was detected in several tissues including the brain and liver of goldfish. Nesfatin-1-like immunoreactive cells are present in the feeding regulatory nucleus of the hypothalamus and in the gastrointestinal tract of goldfish. Approximately 6-fold increase in NUCB2 mRNA levels was found in the liver after 7-day food-deprivation, and a similar increase was also found after short-term fasting. This points toward a possible liver specific role for NUCB2 in the control of metabolism during food-deprivation. Meanwhile, ∼2-fold increase at 1 and 3 h post-feeding and an ∼3-fold reduction after a 7-day food-deprivation was observed in NUCB2 mRNA in the goldfish hypothalamus. In vivo, a single intraperitoneal injection of the full-length native (goldfish; gf) nesfatin-1 at a dose of 50 ng/g body weight induced a 23% reduction of food intake one hour post-injection in goldfish. Furthermore, intracerebroventricular injection of gfnesfatin-1 at a dose of 5 ng/g body weight resulted in ∼50% reduction in food intake.
  
  
  CONCLUSIONS
  Our results provide molecular, anatomical and functional evidences to support potential anorectic and metabolic roles for endogenous nesfatin-1 in goldfish. Collectively, we provide novel information on NUCB2 in non-mammals and an anorexigenic role for nesfatin-1 in goldfish.
authors.affiliation: Laboratory of Integrative Neuroendocrinology, Department of Biology, York University, Toronto, Ontario, Canada.
authors.forename: Ronald
authors.initials: R
authors.lastname: Gonzalez
authors.forename: Brent
authors.initials: B
authors.lastname: Kerbel
authors.forename: Alexander
authors.initials: A
authors.lastname: Chun
authors.forename: Suraj
authors.initials: S
authors.lastname: Unniappan
mesh_terms: D000818:Animals; D001921:Brain / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000378:metabolism; D005260:Female; D006054:Goldfish; D007150:Immunohistochemistry / Q000379:methods; D008099:Liver / Q000378:metabolism; D008297:Male; D009419:Nerve Tissue Proteins; D000080866:Nucleobindins; D036361:Peptide Hormones / Q000235:genetics / Q000494:pharmacology* / Q000502:physiology*; D010802:Phylogeny; D012333:RNA, Messenger / Q000378:metabolism; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; D013997:Time Factors; D014018:Tissue Distribution
chemical_list: D002135:Calcium-Binding Proteins; D004268:DNA-Binding Proteins; D009419:Nerve Tissue Proteins; D000080866:Nucleobindins; D036361:Peptide Hormones; D012333:RNA, Messenger