Ghrelin, cholecystokinin, and peptide YY in Atlantic salmon ( Salmo salar ): Molecular cloning and tissue expression

• Published in: General and comparative endocrinology 2009-02, Vol.160 (3), p.223-235
• Main Authors: Murashita, Koji, Kurokawa, Tadahide, Nilsen, Tom Ole, Rønnestad, Ivar
• Format: Article
• Language: English
• Subjects: Amino Acid Sequence; Animals; Base Sequence; Cholecystokinin; Cholecystokinin - chemistry; Cholecystokinin - genetics; Cholecystokinin - metabolism; Cloning, Molecular; DNA, Complementary - chemistry; Endocrinology & Metabolism; Fish; Fish Proteins - chemistry; Fish Proteins - genetics; Fish Proteins - metabolism; Ghrelin; Ghrelin - chemistry; Ghrelin - genetics; Ghrelin - metabolism; GI tract; Marine; Molecular Sequence Data; Peptide YY; Peptide YY - chemistry; Peptide YY - genetics; Peptide YY - metabolism; Phylogeny; Salmo salar; Salmo salar - genetics; Salmo salar - metabolism; Sequence Alignment; Sequence Analysis, DNA; Sequence Analysis, Protein; Starvation - metabolism; Teleostei; Tissue distribution
• ISSN: 0016-6480; 1095-6840
• DOI: 10.1016/j.ygcen.2008.11.024

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.