title: Ghrelin, cholecystokinin, and peptide YY in Atlantic salmon (Salmo salar): molecular cloning and tissue expression.
abstract: Gastrointestinal (GI) peptide hormones, ghrelin (GHRL), cholecystokinin (CCK), and peptide YY (PYY) genes were identified in Atlantic salmon, Salmo salar. Full-length cDNAs encoding two isoforms of GHRL (GHRL-1 and GHRL-2), two isoforms of CCK (CCK-L and CCK-N) and peptide YY (PYY) cDNA were obtained. The GHRL-1 and GHRL-2 genes encoded proteins of 111- and 108-amino acids, respectively. Both types of GHRL were mainly expressed in the stomach, but also weakly expressed in the pyloric caeca, mid-gut, adipose tissue, and testis. The CCK-L and CCK-N genes encoded preproproteins of 132- and 140-amino acids, respectively. Both types of CCK were strongly expressed in the brain and comparatively weakly expressed in other tissues, including the digestive tract. In the digestive tract, CCK-L was mainly expressed in the pyloric caeca and hind-gut, while CCK-N was only expressed in the pyloric caeca. The PYY gene encoded for 97-amino acid residues and was mainly expressed in the brain and anterior part of the intestine, including the pyloric caeca. In an experiment, we demonstrated that 6 days starvation led to, increased GHRL-1 mRNA levels in the GI tract (stomach), while there no significant changes in expression levels for the other hormones in the GI tract. This suggests an orexigenic role for GHRL-1 in Atlantic salmon. These data contribute to elucidate the functional relationships among teleost gastrointestinal peptide hormones.
authors.affiliation: Tohoku National Fisheries Research Institute, Fisheries Research Agency, Shiogama, Miyagi, Japan.
authors.forename: Koji
authors.initials: K
authors.lastname: Murashita
authors.forename: Tadahide
authors.initials: T
authors.lastname: Kurokawa
authors.forename: Tom Ole
authors.initials: TO
authors.lastname: Nilsen
authors.forename: Ivar
authors.initials: I
authors.lastname: Rønnestad
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D002766:Cholecystokinin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry; D029941:Fish Proteins / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D054439:Ghrelin / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D008969:Molecular Sequence Data; D019894:Peptide YY / Q000737:chemistry / Q000235:genetics / Q000378:metabolism*; D010802:Phylogeny; D020317:Salmo salar / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D017422:Sequence Analysis, DNA; D020539:Sequence Analysis, Protein; D013217:Starvation / Q000378:metabolism
chemical_list: D018076:DNA, Complementary; D029941:Fish Proteins; D054439:Ghrelin; D019894:Peptide YY; D002766:Cholecystokinin