Studies on Hypothalamus-Pituitary-Thyroid Control System of Bullfrog

牛蛙下丘脑-垂体-甲状腺控制系统的研究

基本信息

批准号：
63540594
负责人：
HAYASHI Hiroaki
金额：
$ 1.22万
依托单位：
Institute of Endocrinology, Gunma University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1988
资助国家：
日本
起止时间：
1988 至 1989
项目状态：
已结题

来源：
https://kaken.nii.ac.jp/grant/KAKENHI-PROJECT-63540594/
关键词：
Amphibia Bullfrog TSH TRH TSH放出因子 TSHβ RIA

项目摘要

To clarify the control mechanisms of metamorphosis on Amphibian it is important to isolate and characterize the thyroid stimulating hormone (TSH) and TSH releasing hormone (TRH).We have isolated the TSH from the pituitary glands of bullfrogs, Rana catesbeiana, using various chromatographic techniques. The bioactivity of this preparation, as measured in vitro by the release of T_4 into culture medium from the thyroid gland taken from hypophysectomized prometamorphic bullfrog tadpole, was about 2 times higher than that of bovine TSH. The molecular weight and multiple isoelectric points. of this TSH were about 32,000 and 4.5-5.0, respectively. The amino acid sequence of the alpha-subunit of TSH is identical to those of bullfrog LH and FSH, having about 60% identity to that of mammalian one. However, the amino acid sequence of beta-subunit of this TSH has no homology with mammalian TSH-beta hitherto known, while beta-subunit of bullfrog LH and FSH have resemblance to those of mammalian LH and FSH, 40 and 60 % identities, respectively.A double antibody radioimmunoassay (RIA) system for bullfrog TSH-beta was established using polyclonal antibody after raised against beta-subunit of this TSH. Intact LH, FSH and their subunits from bullfrog did not react in this system. Serum TSH-beta in larval bullfrogs of various developmental stages were measured using this RIA system. Serum TSH-beta levels were relatively low during prometamorphosis. The levels rose markedly at the onset of climax and declined at the end of climax, as in the case of T_4.Synthetic TRH (5-20ug/100g body weight) were injected into the cannulated vena abdominalis of adult bullfrogs. However, no significant elevation of plasma TSH was observed during the experimental period up to 8 hours. These probably suggest the existence of another type TRH in bullfrog.

为了阐明两栖类变态的控制机制，分离和表征促甲状腺激素 (TSH) 和 TSH 释放激素 (TRH) 非常重要。我们使用各种色谱技术从牛蛙 (Rana catesbeiana) 的垂体中分离出 TSH。。通过从垂体切除的原变态牛蛙蝌蚪的甲状腺向培养基中释放T_4进行体外测量，该制剂的生物活性比牛TSH高约2倍。分子量和多个等电点。该 TSH 分别约为 32,000 和 4.5-5.0。 TSH的α亚基的氨基酸序列与牛蛙LH和FSH的氨基酸序列相同，与哺乳动物的氨基酸序列有约60%的同一性。然而，该TSH的β亚基的氨基酸序列与迄今为止已知的哺乳动物TSH-β没有同源性，而牛蛙LH和FSH的β亚基与哺乳动物LH和FSH的相似性分别为40％和60％ .使用针对牛蛙TSH-β亚基的多克隆抗体建立了牛蛙TSH-β的双抗体放射免疫测定(RIA)系统。来自牛蛙的完整 LH、FSH 及其亚基在该系统中不发生反应。使用该 RIA 系统测量了不同发育阶段牛蛙幼虫的血清 TSH-β。变态期血清TSH-β水平相对较低。与T_4的情况一样，在高潮开始时水平显着上升，在高潮结束时下降。将合成TRH（5-20ug/100g体重）注射到成年牛蛙的插管腹腔静脉中。然而，在长达 8 小时的实验期间，没有观察到血浆 TSH 显着升高。这些可能表明牛蛙中存在另一种类型的TRH。