頁籤選單縮合
題 名 | Multiple Neuroendocrine Regulation of Growth Hormone in the European Eel Anguilla anguilla |
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作 者 | Dufour,Sylvie; Rousseau,Karine; Sbaihi,Miskal; Belle,Nadine Le; Vidal,Bernadette; Marchelidon,Jacques; Schmitz,Monika; | 書刊名 | 水產研究 |
卷 期 | 9:1/2 民90.12 |
頁 次 | 頁77-92 |
分類號 | 388.491 |
關鍵詞 | Eel; GH; SRIH; CRH; PACAP; |
語 文 | 英文(English) |
英文摘要 | Growth hormone (GH) is involved in the control of various physiological functions in teleosts, including not only body growth but also reproduction, osmoregulation, metabolism and immunity. Most data on GH regulation come from investigations in mammals and studies in teleosts suggest important species-related variations. We developed specific tools to investigate GH regulation in the European eel: purification of pituitary GH, obtention of specific antibodies and development of homologous radioimmunoassay (RIA), cloning of pituitary GH cDNA and obtention of a specific probe for messenger RNA assays, development of an eel pituitary cell culture system for short- and long-term studies of GH synthesis and release. Investigations on the neuroendocrine control of GH in the eel demonstrated multiple regulations and interactions with other major neuroendocrine axes involved in development, growth, metabolism, and reproduction. Eel somatotrophs exhibit a high autonomous activity. A brain neurohor-mone,somatostatin (SRIH) exerts a major inhibitory control on GH in the eel as in other teleosts. This inhibitory control has been conserved throughout vertebrate evolution. Insulin-like growth factrors (IGFs), produced by the liver in response to GH, exert a negative feedback on GH synthesis and release, an inhibitory control also strongly conserved among vertebrates. In contrast, GH-releasing factors show large variations among vertebrates and even teleosts. Pituitary adenylate cy-clase-activating polypeptide (PACAP), stimulates GH release in the eel as well as in the other teleosts investigated, and may represent an ancestral GH-releasing factor progressively replaced by somatoliberin (GHRH) in tetrapods. Other neurohormones such asgonadoliberins, thyroliberin, dopamine, neuropetide Y, or cholecystokinin, found to exert GH-releasing effects in some but not all teleosts, were inactive on GH release in the eel. In contrast, corticoliberin (CRH) had a strong GH-releasing effect inthe eel, a role possibly related to special developmental and physiological events of the eel biological cycle, such as metamorphosis, fasting, and migration. |
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