Cholecystokinin and peptide Y in yellowtail (Seriola quinqueradiata): molecular cloning, real-time quantitative RT-PCR, and response to feeding and fasting.
In fish, the peptide hormones cholecystokinin (CCK) and peptide Y (PY) may be involved in pancreatic exocrine secretion, as found with mammalian CCK and peptide YY (PYY); CCK stimulates, whereas PYY inhibits, pancreatic exocrine secretion in mammals. However, there is very little information on these hormones in fish; in particular, the function of PY is still unknown. Therefore, as a first step for understanding the role of CCK and PY in regulating pancreatic exocrine in fish, the cDNAs of CCK and PY were cloned from the digestive tract of yellowtail (Seriola quinqueradiata). The peptide sequence of yellowtail CCK-8, DYLGWMDF, is identical to sequences found in several teleosts. The mature form of yellowtail PY consists of 36 amino acids and has high identity to other fish PYs (88.9-97.2%). Real-time quantitative RT-PCR assays were developed to measure yellowtail CCK and PY mRNA levels. CCK mRNA levels were extremely high in the brain and, among the digestive organs, high concentrations were found in the pyloric caeca and anterior intestine. PY mRNA levels were low in the brain and highest in the anterior intestine. In fasting experiments, mRNA levels of CCK and PY in the anterior intestine showed an antagonistic change after fasting; CCK decreased whereas PY increased. These data suggest that CCK and PY in yellowtail may relate to digestion including, enzyme secretion.
Murashita
Koji
K
Faculty of Agriculture, Kochi University, B200 Monobe, Nankoku, Kochi 783-8502, Japan.
Fukada
Haruhisa
H
Hosokawa
Hidetsuyo
H
Masumoto
Toshiro
T
D000595:Amino Acid Sequence; D000818:Animals; D001483:Base Sequence; D001921:Brain / Q000378:metabolism; D002766:Cholecystokinin / Q000235:genetics*; D003001:Cloning, Molecular; D018076:DNA, Complementary / Q000737:chemistry / Q000235:genetics; D005215:Fasting; D005247:Feeding Behavior; D029941:Fish Proteins / Q000235:genetics; D005704:Gallbladder / Q000378:metabolism; D015870:Gene Expression / Q000235:genetics*; D020869:Gene Expression Profiling; D007413:Intestinal Mucosa / Q000378:metabolism; D008969:Molecular Sequence Data; D009478:Neuropeptide Y / Q000235:genetics*; D010473:Perciformes / Q000235:genetics*; D010802:Phylogeny; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017422:Sequence Analysis, DNA; D017386:Sequence Homology, Amino Acid
D018076:DNA, Complementary; D029941:Fish Proteins; D009478:Neuropeptide Y; D012333:RNA, Messenger; D002766:Cholecystokinin