碩士 / 國立高雄海洋科技大學 / 水產養殖研究所 / 101 / The high levels of estradiol-17β in plasma of yellowfin porgy, Acanthopagrus latus, were found during oocyte maturation, which function was still unclear. In the present study, the expression of estrogen receptor (er) and related genes in ovary and liver, and bioassay with oocytes by E2 were measured to find the potential role of E2 in the fish.
The results showed that high levels of ers (erα, erβ1, erβ2, gper) and cyp19a1a were expressed in liver, gonad and brain of yellowfin porgy. High levers of ers were observed in the ovary during spawning season. The expression levels of erβ1 and erβ2 in the liver were significantly increased before and during spawning season, respectively. Gper was predominantly expressed in mature oocytes, while cyp19a1a showed the highest expression levels in ovary at vitellogenic and maturation stage.
The expression of erα in the liver, plasma vitellin and HSI were significantly increased by E2 treatments of male fish with hermaphroditic gonad in non-spawning season. It indicated that the functions of erα were involved in vitellogenesis in the fish. In addition, erβ1 and erβ2 were correlated with development of gonad. The in vitro study showed that E2 inhibit the GVBD by GPER. During FOM, E2 might involve in stimulate vitellogenesis and inhibite FOM in the ovarian; moreover, the weight gain during FOM was associated with oocyte responsive to hormone in the female fish could be applications for artificial reproduction in fish.
In ovary, the different growth stage of oocytes during FOM, high levels of expressions of erα, erβ1 and erβ2 were observed in the diameter of oocytes between 200~300μm and 400μm groups. The expressions of Cyp19a1a, were increased significantly after LHRH-A treatment in ovary, and had the highest expression in the diameter of oocytes at 200-300μm. The levels of gper expression were increased in GVBD stage in the diameter of oocytes at 700μm. These results suggested that erα, erβ1 and erβ2 expression were regulated by E2 for the development of immature oocytes (200-300μm and 400μm). Gper might be involved in control GVBD and co response with mPRα in FOM.
Although ERs were nuclear receptors in teleosts, the present results of immunohistochemistry for ERα and ERβ1 were observed in oocyte near plasma membrane in the fish. It needed for the further discussion in the future. Gper was confirmed as an estrogen membrane receptor, cyp19a1a was predominantly expressed in follicle cells.
In conclusion, these results of this study showed that erα might be involved in vitellogenin synthesis in liver; erβ1and erβ2 were associated with previtellogenic stage of oocytes, and gper inhibited GVBD of full-grown stage oocytes (400μm). The possible models of E2 in ovarian growth were oocyte developed by erβ1 and erβ2 during previtellogenic stage. In vitellogenic stage, E2 was created by cyp19a1a and might react to liver to up regulated erα expression and vitellogenesis. In ovary, the expressions of erα were increased by GtH and responsive with E2 for the vitellogenin accumulated to oocyte. During FOM, E2 reacted to GPER for inhibited GVBD in full-grown stage oocytes and co regulated multiple spawning by mPRα and MIS in yellowfin porgy.
| Identifer | oai:union.ndltd.org:TW/101NKIM0086003 |
| Date | January 2013 |
| Creators | Shu-Fang Sun, 孫淑芳 |
| Contributors | Wen-Shiun Yueh, 岳文勛 |
| Source Sets | National Digital Library of Theses and Dissertations in Taiwan |
| Language | zh-TW |
| Detected Language | English |
| Type | 學位論文 ; thesis |
| Format | 219 |
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