2006 Fiscal Year Final Research Report Summary
Study on mechanism of growth hormone-dependent and-independent functions of ghrelin in
| Project/Area Number |
17380176
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Basic veterinary science/Basic zootechnical science
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| Research Institution | Nippon Veterinary and Life Science University |
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Principal Investigator |
TANAKA Minoru Nippon Veterinary and Life Science University, Faculty of Applied Life Science, Department of Animal Science, Professor, 応用生命科学部, 教授 (90024736)
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| Co-Investigator(Kenkyū-buntansha) |
SAITO Toru Nippon Veterinary and Life Science University, Faculty of Veterinary Medicine, Department of Veterinary Medicine, 獣医学部, 教授 (70211258)
OHTA Yoshiyuki Nippon Veterinary and Life Science University, Faculty of Applied Life Science, Department of Animal Science, Associate Professor, 応用生命科学部, 助教授 (00277667)
FURUTA Hiroki Nippon Veterinary and Life Science University, Faculty of Applied Life Science, Department of Animal Science, Assistant Professor, 応用生命科学部, 助手 (30366794)
YAMAMOTO Ichiro Nippon Veterinary and Life Science University, Faculty of Veterinary Medicine, High-Tec Research Center, 獣医学部, ポストドクター (00424763)
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| Project Period (FY) |
2005 – 2006
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| Keywords | Ghrelin / Ghrelin receptor / Chicken / Growth hormone / Growth hormone receptor / Dwarf / GPR39 / Tissue expression |
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| Research Abstract |
1. To investigate the effect of excess GH secretion in the pituitary of a sex-linked dwarf chicken, we measured expression level of ghrelin mRNA in the proventriculus which is a major tissue for ghrelin production. Real-time PCR analysis revealed that the excess secretion of GH has no effect on the expression level of ghrelin gene. Parallel increases were observed in the expression levels of ghrelin mRNA in the proventriculus and GH mRNA in the pituitary from embryonic day 17 to day 7 after hatch. These results suggest that proventriculus-derived ghrelin participate in pituitary GH synthesis by acting on its receptor during this period.
2. GPR39 is an orphan receptor structurally related to ghrelin receptor. we performed cDNA cloning for chicken and Japanese quail GPR39 and characterized tissue-expression profiles of their mRNAs. The amino acid sequence of both the avian GPR39 showed high homology to mammalian GPR39. A computer-assisted search for chicken GPR39 cDNA sequence in the chicken genome database revealed that chicken GPR39 gene consists of two exons separated by an intron. Real-time PCR analysis revealed the expression of GPR39 mRNA in a wide range of tissues with the highest level in the digestive tissues in chicken and quail. In the chicken, the expression level in the duodenum rapidly increased during the early post-hatch period. Interestingly, relatively higher expression was observed in the oviduct, vagina and uterus in hen. These findings suggest that GPR39 is involved in the regulation of gastrointestinal and reproductive functions in chicken.
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