Please use this identifier to cite or link to this item:
Gene Expression of Somatolactin and Proopiomelanocortin in relation to Environmental Stress in Black Porgy, Acanthopagrus schlegeli
|Authors: ||Yuan-Fang Wang|
|Contributors: ||NTOU:Department of Aquaculture|
cold stress;environmental adaptation;cortisol;stress response;sex steroids;black porgy
|Issue Date: ||2011-06-30T08:39:00Z
|Abstract: ||本研究之目的了解腦下垂體somatolactin (SL)的功能以及proopiomelanocortin (POMC)這兩個基因經過緊迫刺激後的基因表現。本實驗以海水魚黑鯛作為研究魚種，成功的選殖到這兩個基因之胺基酸序列，並設計特異性引子以作為基因之探針，以real-time PCR之分析方式來了解SL於環境緊迫適應中表現以及緊迫因子造成在下視丘-腦下垂體-腎上腺皮質(hypothalamic-pituitary-interrenal, HPI) 反應中，主宰ACTH分泌的前驅物POMC的表現。 在低溫緊迫(19.5 ℃→14 ℃)之環境下黑鯛SL會於緊迫源解除後24小時顯著的增加，於另一種注射低劑量(0.5 μg/g BW) cortisol緊迫源，SL表現顯著地上升。在注射性類固醇實驗中發現estradiol-17β (E2)及testosterone (T) 對腦下垂體SL表現是有顯著地影響，顯示SL表現和性類固醇分泌或生殖方面具有相關性。另外水生動物最敏感鹽度所造成緊迫，在原本於淡水生活的黑鯛急速改變至海水中4天後，SL表現有顯著地下降。 POMC於低溫緊迫時會有顯著增加表現，但直接注射cortisol腦下垂體POMC表現與控制組間無顯著差異。性類固醇E2及T注射實驗中以及長期適應或急速改變鹽度的實驗中未發現POMC有顯著表現。 這些研究得結果顯示出在不同環境的環境所造成的緊迫所感受到緊迫程度不同，SL及POMC表現牽涉其中，對於SL這個基因在環境適應中是乎扮演一個極重要的角色，而對於構成緊迫反應中，POMC基因表現多寡亦為一個重要元素。|
The objective of the present study was to examine the stimulatory effect of stressors on the somatolactin and proopiomelanocortin gene expression in the pituitary of black porgy, Acanthopagrus schlegeli. The nucleotide sequences of SL and POMC mRNA were determined in pituitary, and specific primers were designed for real-time PCR to measure SL and POMC gene expression in response to stress. Slight cold stress (19.5 ℃→14 ℃) resulted in an increase in SL gene expression after 24 hrs treatment. Response to low dose cortisol injection (0.5 μg/g BW) was measured immediately after administration of the hormone and the result showed that SL gene expression was increased significantly. Similarly, SL gene expression also showed a significant increase in response to sex steroid injection. These results suggest that SL may be associated with reproduction. Under different salinities, the SL gene expression decreased when BP was transferred from FW to SW on the 4th day, indicating that SL gene expression may also be related to FW adaptation. POMC gene expression increased significantly during cold stress, but gene expression of POMC was not significantly different between low and high dose of cortisol treatment. Different salinities or injection with different sex steroids did not cause any significant change in POMC expression. In the present study, the major physiological functions of SL remain unclear. But SL may be associated with environmental adaptation. In HPI axis, stressor can influence hypothalamus to secrete CRH which in turn acts upon pituitary to secrete ACTH. Thus, POMC may play an important role in stress response and also in homeostatic balance.
|Appears in Collections:||[水產養殖學系] 博碩士論文|
Files in This Item:
All items in NTOUR are protected by copyright, with all rights reserved.