中文摘要：

目前河流中存在较高浓度的天然和人造糖皮质激素（如皮质醇等）污染,其可能对鱼类的渗透压调节和海河洄游产生影响.鱼类鳃内钠钾ATP酶对调节渗透压平衡、适应海河洄游等起关键性作用,有研究表明鱼类鳃内钠钾ATP酶基因表达受皮质醇调控.为此,论文克隆了青鳉钠钾ATP酶α和钠钾ATP酶β基因的序列片段,建立了实时定量RT-PCR测定方法,研究了盐度的增加对其基因表达的影响,并重点探讨了皮质醇对鱼类适应盐度时鳃内钠钾ATP酶基因表达变化的影响.结果表明,适应15‰盐水的青鳉鳃内钠钾ATP酶α和钠钾ATP酶β基因表达显著升高;在转入淡水48h后,钠钾ATP酶α和钠钾ATP酶β基因表达基本恢复到正常水平,但是转入含有100ng·L^-1皮质醇暴露水平的淡水中,48h后钠钾ATP酶α基因表达仍处于较高水平,表明100ng·L^-1浓度的皮质醇能够显著诱导鳃内钠钾ATP酶α的基因表达,可能干扰渗透压调节,对一些洄游鱼类的溯河过程可能构成潜在影响.

英文摘要：

Studies have reported nigher levels of （natural or man-made）glucocorficoids （such as cortisol） in the aquatic environments which may affect the osmoregulation in anadromous migration of fishes. Na^＋-K^＋-ATPase plays important role in the course of anadromous migration which is known to be regulated by cortisol in teleost. In this study, the partial length genes encoding the α and β subunits of Na^＋-K^＋-ATPase were cloned from medaka gill. The effects of cortisol on the transcrpfional expression of Na^＋-K^-ATPase α and β subunit genes were studied by quantitative real-time PCR method. The medaka which had been acclimated to saltwater of 15‰ were transferred to freshwater containing 0（control）, 10, 100ng·L^-1 cortisol for 48 hours. Results showed that 100ng·L^-1 of cortisol significantly obstructed the decrease of the expression Na^＋-K^＋-ATPase α mRNA, which would disturb the normal hypoosmoregulation during the fish migration of oceanic diadromous fish.