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Physiological actions of a family of natriuretic peptides in eels

鳗鱼钠尿肽家族的生理作用

基本信息

批准号：
04640691
负责人：
TAKEI Yoshio
金额：
$ 1.28万
依托单位：
Ocean Research Institute, University of Tokyo
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1992
资助国家：
日本
起止时间：
1992 至 1993
项目状态：
已结题

项目摘要

I.We cloned cDNA of eel atrial natriuretic peptide (ANP). The C-terminus of proANP predicted from the cDNA sequence has glycine residue which could not read by the amino acid sequencing. Detailed HPLC analysis revealed that glycine residue was used for amidation of the C-terminus of ANP.Southern blot analysis indicated that ANP and VNP genes are present in birds. Since BNP has already been identified in birds, VNP appears to be a new hormone distinctly different from BNP.II.In cooperation with Professor S.Hirose of Tokyo Institute of Technology, we cloned cDNAs of eel ANP-B and ANP-C receptors. By means of autoradiography and radioligand binding assay, we found dense population of ANP-C receptors in the gill cartilage as well as gill cells.III.Plasma ANP levels increased immediately after transfer of eels from fresh water to seawater. However, in eels adapted to seawater for two weeks, plasma ANP levels decreased significantly from the freshwater levels. The ANP level in the dorsal aorta was decreased to half compared with the level in the ventral aorta, which is explained by the extraction of ANP by ANP-C receptors in the gill.IV.ANP inhibited water intake and intestinal water and sodium absorption in the eel. ANP also caused antidiuresis and increased cortisol excretion. The former actions on the brain and intestine are advantageous to freshwater adaptation, but the latter two actions, antidiuretic and steroidogenic actions, are favorable to seawater adaptation. Thus it is not yet established whether ANP is a freshwater-adapting hormone or seawater adapting hormone in the eel.

一、我们克隆了鳗鱼心钠素（ANP）的cDNA。从cDNA序列预测proANP的C末端有甘氨酸残基，氨基酸测序无法读取。详细的 HPLC 分析表明，甘氨酸残基用于 ANP C 末端的酰胺化。Southern 印迹分析表明，ANP 和 VNP 基因存在于鸟类中。由于BNP已在鸟类中被发现，VNP似乎是一种与BNP明显不同的新激素。II。我们与东京工业大学S.Hirose教授合作，克隆了鳗鱼ANP-B和ANP-C受体的cDNA。通过放射自显影和放射性配体结合测定，我们发现鳗鱼的鳃软骨和鳃细胞中存在密集的ANP-C受体。三、鳗鱼从淡水转移到海水后血浆ANP水平立即升高。然而，鳗鱼适应海水两周后，血浆 ANP 水平较淡水水平显着下降。背主动脉的ANP水平比腹主动脉的水平降低了一半，这可能是由于鳃中的ANP-C受体提取ANP所致。四、ANP抑制了鳗鱼的水摄入和肠道水和钠的吸收。 ANP 还会引起抗利尿作用并增加皮质醇的排泄。前一种对大脑和肠道的作用有利于淡水适应，而后两种作用，即抗利尿作用和类固醇作用，有利于海水适应。因此，ANP 是鳗鱼中的淡水适应激素还是海水适应激素尚未确定。