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|Authors: ||Hung-Wen Li|
|Contributors: ||NTOU:Department of Aquaculture|
|Issue Date: ||2011-06-30T08:39:16Z
|Abstract: ||本實驗之目的有兩大主題，第一個主題是探討arginine vasotocin (AVT) 與其受體(arginine vasotocin V1 type receptor, AVTR-V1) 基因在黑鯛不同生殖發育階段表現之變化，尤其與黑鯛性別分化之關係；另一主題為探討鹽度變化與黑鯛AVT基因表現變化之關係。 黑鯛生殖腺性別分化約為孵化後120到150天，而黑鯛下視丘AVT基因在孵化後第120天大量表現，因此推測AVT基因應與性別分化有關。黑鯛下視丘的AVT基因在第1、2及第3年繁殖季顯著表現，而前腦AVT基因表現則在第1及第2年的非繁殖季顯著表現，推測下視丘AVT基因的表現應與生殖腺之發育成熟及生殖行為有關，而前腦AVT基因的表現應與其他生理機制比較相關。在投餵含AI (aromatase inhibitor) 的飼料15天之後，會促進AVT基因在下視丘的表現，投餵45天之後，則會明顯地抑制AVT基因在中腦及下視丘的表現；不論投餵AI飼料15或45天均會促進AVTR-V1在生殖腺的表現。在注射性類固醇激素的實驗中發現，高劑量的11-KT (11-ketotestosterone) 會促進AVT基因在下視丘的表現，而不論高、低劑量T (testosterone) 及E2 (estradiol) 的注射對下視丘AVT基因並無顯注的影響，所以AVT基因表現會受到性類固醇激素影響，但要視其種類及劑量而定。 黑鯛AVT基因表現在急速從淡水轉移至海水的第8個小時會明顯增加，而在急速從海水轉移至淡水的第3天則會顯著地下降，因此推測黑鯛AVT基因應與海水的適應有關。在投餵含高劑量的cortisol 的飼料7天之後，黑鯛下視丘的AVT基因表現明顯地受到抑制，但其作用機制仍然未知。|
The objectives of the present study were to investigate the molecular role of AVT and AVTR V1 genes in the sexual development and salinity tolerance of the protandrous black porgy (Acanthopagrus schlegeli). The variation of AVT and AVTR V1 gene expression was studied at different reproductive development stage of black porgy, especially in relation to sex differentiation. Changes in the gene expression after administration of sex steroids were also investigated. Gonadal sex differentiation in black porgy occurs between 120~150 dah (days after hatching), but hypothalamus AVT gene increased significantly at 120 dah, indicating that AVT might be related to sex differentiation in black porgy. Hypothalamus AVT gene increased significantly during spawning season of 1~3 year old black porgy. In contrast, in the forebrain, AVT gene increased significantly during non-spawning season of 1 and 2 year old fish. Therefore, we suggest that expression of hypothalamus AVT gene might be related to gonadal development and maturation or sex behaviors of black porgy. Oral administration of ATD for 15 days resulted in a significant increase in the expression of hypothalamus AVT gene and gonad AVTR V1 gene, whereas oral administration of ATD for 45 days resulted in a significant decease in the expression of midbrain and hypothalamus AVT gene and an increase in the expression of gonad AVTR V1 gene. Injection of high dose 11-ketotestosterone caused a significant increase in the expression of hypothalamus AVT. In contrast, testosterone and 17β estradiol had no significant influence on hypothalamus AVT. Thus, we suggest that sex steroids could influence the gene expression of AVT in a dose dependent manner. Transfer of black porgy from freshwater to seawater for 8 hours resulted in a significant increase in the expression of hypothalamus AVT gene, while transfer from seawater to freshwater for 3 days resulted in a significant decrease in the expression of hypothalamus AVT gene. Oral administration of high dose cortisol for 7 days caused a significant decrease in the expression of hypothalamus AVT gene, but the regulatory mechanism is still unclear.
|Appears in Collections:||[水產養殖學系] 博碩士論文|
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