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Endocrinological analysis of amphibian life cycle

两栖动物生命周期的内分泌分析

基本信息

批准号：
01440005
负责人：
KIKUYAMA Sakae
金额：
$ 15.62万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (A)
财政年份：
1989
资助国家：
日本
起止时间：
1989 至 1992
项目状态：
已结题

项目摘要

Endocrinological analysis of biological phenomena such as metamorphosis, growth and reproduction in amphibian life cycle were performed. 1)Metamorphosis Amphibian metamorphosis is mainly under the control of three hormones, namely, thyroid hormone, adrenocortical hormone and prolactin. Our study was focused on prolactin gene expression during metamorphosis. Using bullfrog and toad prolactin cDNA, we have revealed that prolactin mRNA levels rise as metamorphosis progresses. This indicates that the elevation of plasma and pituitary prolactin levels during metamorphic climax accompanies the elevation of prolactin synthesis. The enhacement of prolactin cell function in the pituitary during metamorphic climax is presumed to be related with the maturation of adult organs which develop in this period. In fact, we have demonstrated that prolactin increases phospholipids in the lung surfactant. 2)Growth We have purified amphibian growth hormone from the bullfrog pituitary. Using this preparatio … More n, primary structure of amphibian growth hormone was determined. Homologous radioimmunoassay system was also developed. It was revealed that growth hormone levels rise as metamorphosis progresses and reaches maximum when the animals completed metamorphosis. Growth hormone mRNA levels are also high in the juvenile frogs. This indicates that in juveniles a marked growth occurs. As regards the mode of action of growth hormone, presence of a growth hormone mediator in the plasma, as in the case in mammals, was demonstrated in Xenopus. 3)Reproduction Hormonal control of courtship behavior in the newt, Cynops pyrrhogaster was studied. Sexually mature male of this species vibrates the tail in front of sexually mature female at the initial stage of courtship. It was reveled that both incidence and frequency of the tail vibration behavior are enhanced by prolactin and androgen (testosterone or dihydrotestosterone). Moreover the male releases a sex attractant into the water. It was revealed that the attractant is secreted from the abdominal glands of the cloaca. The development of the abdominal glands is also under the control of prolactin and androgen. It was demonstrated that this attractant is a peptide of molecular weight below 5,000. Less

对两栖动物生活史中的变态、生长和繁殖等生物现象进行了内分泌学分析。1)变态两栖动物的变态主要受三种激素控制，即甲状腺激素、肾上腺皮质激素和催乳素。我们的研究重点是催乳素基因在变态过程中的表达。利用牛蛙和蟾蜍的催乳素基因，我们发现随着变态的进行，催乳素的mRNA水平也会升高。这表明，在变态过程中，血浆和垂体催乳素水平的升高伴随着催乳素合成的升高。催乳素细胞功能在变态顶峰时期的增强被认为与在此时期发育的成年器官的成熟有关。事实上，我们已经证明催乳素增加了肺表面活性物质中的磷脂。2)生长我们从牛蛙脑垂体中提纯了两栖类生长激素。使用这种制剂…进一步确定了两栖类生长激素的一级结构。并研制了相应的放射免疫分析系统。结果表明，随着变态的进行，生长激素水平逐渐升高，在变态完成时达到最大值。幼蛙体内的生长激素mRNA水平也很高。这表明，青少年会有显著的生长发育。至于生长激素的作用方式，在非洲爪哇中，证明了血浆中存在生长激素介体，就像哺乳动物的情况一样。3)研究了繁殖荷尔蒙对食蟹鱼求偶行为的控制。这一物种的性成熟雄性在求爱的初始阶段在性成熟的雌性面前摇动尾巴。研究发现，催乳素和雄激素(睾酮或双氢睾酮)都能增加尾部振动行为的发生率和频率。此外，雄性向水中释放一种性引诱剂。据透露，引诱剂是从泄殖腔的腹腺中分泌出来的。腹腺的发育也受催乳素和雄激素的控制。结果表明，该引诱剂是一种相对分子质量小于5,000的多肽。较少