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Studies on the regulation of aromatase activity in mature female ice goby

成熟雌性冰虎鱼芳香酶活性调控的研究

基本信息

批准号：
13660194
负责人：
ASAHINA Kiyoshi
金额：
$ 2.05万
依托单位：
Nihon University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (C)
财政年份：
2001
资助国家：
日本
起止时间：
2001 至 2002
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-13660194/
关键词：
ice goby maturation aromatase cDNA cloning A type B type B-type 卵巣型

项目摘要

Ice goby, Leucopserion petersi, is a small anadromous fish. Females enter the river with yolk-accumulating ovaries, then, vitellogenesis once stops in the river, and the ovaries rapidly develop in the nest before spawning. To clarify the endocrinological mechanisms of this discontinuation of yolk accumulation, effects of gonadotropins (GTHs) on estradiol-17β (E_2) production were investigated in vitro, using the ovaries of females captured in the river. Of GTHs tested, salmon pituitary extract (SPE) was effective in E_2 production at higher doses (1-10μg/mL). Human chorionic gonadotropin and pregnant mares' serum gonadotropin also showed a significant effect (1-10 IU/mL). Actinomycin D and cycloheximide significantly inhibited E_2 production stimulated by SPE. In the absence of GTHs ovary fragments produced only a marginal amout of E_2. These results indicate that the resting ovaries from the fish captured just after entering the river have rather low aromatase (P450 arom) activity, but it is evoked by the administrations of GTHs. For further studies, P450 arom cDNA was cloned from the developing ovaries. The cDNA encoding ice goby P450 arom (A type) was 1997bp in length and encoded a putative protein of 517 amino acids. The level of A type P450 arom mRNA expression was low in the river but rapidly increased in the nest. From the head containing the brain, another type of P450 arom cDNA was cloned (possibly B type). The deduced amino acid sequence of the A type P450 arom shared about 60% homology with that of B type.

白鳞鱼（Leucopserion petersi）是一种小型的溯河产卵鱼类。雌鱼带着卵巢进入河流，卵黄发生在河流中停止，产卵前卵巢在巢中迅速发育。为了阐明卵黄积累中断的内分泌机制，本研究采用体外培养的方法，研究了促性腺激素（GTH）对雌鱼卵巢17β-雌二醇（E_2）分泌的影响。在所测GTH中，鲑鱼垂体提取物（SPE）在较高剂量（1-10μg/mL）下对E_2的产生有促进作用。人绒毛膜促性腺激素和孕妇血清促性腺激素也显示出显著效果（1-10 IU/mL）。放线菌素D和放线菌酮显著抑制SPE刺激的E_2产生。在缺乏GTH的情况下，卵巢碎片仅产生少量的E_2。这些结果表明，刚进入河流后捕获的鱼的休眠卵巢具有相当低的芳香化酶（P450 arom）活性，但它是由GTH的管理引起的。为了进一步研究，从发育中的卵巢中克隆了P450 arom cDNA。结果表明，冰虾虎鱼P450 arom（A型）的cDNA全长为1997 bp，编码517个氨基酸。A型P450 arom mRNA的表达水平在河中较低，但在巢中迅速增加。从含脑的头部克隆到另一种类型的P450 arom cDNA（可能是B型）。A型与B型P450 arom的氨基酸同源性约为60%。