| Project/Area Number |
59860021
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| Research Category |
Grant-in-Aid for Developmental Scientific Research
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| Allocation Type | Single-year Grants |
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| Research Field |
Fisheries chemistry
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| Research Institution | Kitasato University |
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Principal Investigator |
KAWAUCHI Hiroshi Kitasato University, School of Fisheries Sciences, 水産学部, 教授 (70050523)
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| Co-Investigator(Kenkyū-buntansha) |
MORI Takao University of Tokyo, School of Sciences, 理学部, 助手 (80011659)
SUZUKI Keiji Kitasato University, School of Fisheries Sciences, 水産学部, 助教授 (80050459)
HIRANO Tetsuya University of Tokyo, Ocean Research Institute, 海洋研究所, 教授 (70013571)
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| Project Period (FY) |
1984 – 1986
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| Project Status |
Completed (Fiscal Year 1986)
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| Budget Amount *help |
¥11,500,000 (Direct Cost: ¥11,500,000)
Fiscal Year 1986: ¥1,600,000 (Direct Cost: ¥1,600,000)
Fiscal Year 1985: ¥2,900,000 (Direct Cost: ¥2,900,000)
Fiscal Year 1984: ¥7,000,000 (Direct Cost: ¥7,000,000)
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| Keywords | fish growth hormone / primary structure / ell growth hormone / salmon growth hormone / cDNA / cloning / osmoregulation / stimulation of fish growth / 塩基配列 / 分子進化 / 液浴 / 胃内投与 / ラジオイムノアッセイ / 浸透圧調節 / CDNA / サケ成長ホルモン / ウナギ成長ホルモン / コイ成長ホルモン / 成長促進 / 遺伝子組換え / 脳下垂体 / 免疫組織染色 / 海水適応 |
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| Research Abstract |
This investigation characterized the growth stimulating potential of growth hormones (GH) isolated form two species of economically important fish. GHs purified from an alkaline extract of chum salmon (Oncorhynchus keta) pituitary glands and from a culture medium of eel (Anguilla japonica) pituitary glands were chemically characterized. cDNA clones encoding these fish GHs were isolated from cDNA libraries prepared from pituitary gland poly(A) <^+RNAs> , using synthetic DNAs corresponding to the amino acid sequence of the hormones. The cDNAs of salmon and eel GH were cloned and expressed in E. coli. Salmon and eel GHs synthesized by genetically engineered bacteria (recombinant GHs) had potency equivalent to the natural GHs. Salmonid growth could be stimulated by intraperitoneal injections at doses of 10-100ng/g body weight.
Possible routes for administration of these hormones to fish were investigated. Immersion of salmonid fish into solution of the recombinant salmon GH stimulated the g
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rowth at concentrations of 0.15 to 1.5 <micro> M. Furthermore, oral administration of the recombinant salmon GH could stimulate growth of young rainbow trout at a dose of 10 <micro> g/fish. The blood level of GH, detected by salmon GH radioimmunoassay. increased significantly at 15-18 hour after the administration.
It was also confirmed that GHs play an important role in regulating osmotic pressure of seawater-adapting fish, while prolactin (PRL) regulates osmotic pressure in freshwater-adapting fish.
A second major goal of our work was to study structure-function relationships of the important regulatory hormone. Since PRLs show close chemical resemblance to GH, they have been thought to have evolved from a common ancestral molecule by gene duplication. In order to obtain better insight into the molecular evolution or structure-function relationships. fish PRLs were also characterized. The sequence comparisons of GHs and PRLs showed the occurrence of conserved structures, suggesting that they may be responsible for their biological activities. On the basis of the sequence comparison, the time of divergence of GH and PRL from the common ancestral molecule was estimated to be about 500 million years ago. Less
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