Prolactin gene expression and gill chloride cell activity in fugu Takifugu rubripes exposed to a hypoosmotic environment
Prolactin gene expression and gill chloride cell activity in fugu Takifugu rubripes exposed to a hypoosmotic environment
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DOI：
10.1016/j.ygcen.2006.06.009
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发表时间：
2006-12-01
影响因子：
2.7
通讯作者：
Aida, Katsumi
中科院分区：
文献类型：
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作者：
Lee, Kyung Mi;Kaneko, Toyoji;Aida, Katsumi
为了评估催乳素（PRL）在红鳍东方鲀（Takifugu rubripes）耐低盐性中的可能作用，研究了暴露于25%稀释海水（SW）的鱼类垂体PRL和垂体调节器官PRL受体（PRLR）的基因表达谱。从全强度（100%）SW转换为25% SW后，第1天血浆渗透压摩尔浓度以及Na+和Cl-水平略微降低，第3天和第7天恢复。25%SW处理后，垂体PRL mRNA的表达水平显著升高，而生长激素（GH）mRNA的表达水平显著降低。这些配置文件表明，PRL和GH分别参与hyper和hyporegulation调节，是广盐性硬骨鱼的情况下。鳃和肠中PRLR mRNA的表达水平与初始水平无显著差异，而肾脏中PRLR mRNA的表达在第7天显著高于初始水平。虽然转移到25%SW并不影响鳃中Na+/K+-ATP酶免疫反应阳性氯细胞的平均大小，但转移到25%SW后氯细胞的大小和顶端开口的密度均显著减小。这些结果表明，PRL的低渗作用可能是由垂体调节器官中表达的PRLR介导的，河豚的低盐耐受性可能涉及鳃氯细胞离子分泌功能的降低。为了进一步评估低盐度环境对生长和盐度调节的长期影响，将河豚在25%和100%SW中饲养8周。它们在25%和100% SW中的生长相似，并且在任何每周采样点的体重和标准长度均无显著差异。在两种培养基中，血浆渗透压均维持在345 mOsm/kg中心点H2O左右，但鳃Na+/K+-ATP酶活性在25% SW中显著低于100% SW，垂体PRL基因表达在25% SW中高于100% SW;相反，生长激素的表达水平低于25%SW比在100%SW。这些研究结果支持高渗作用的PRL和低渗，而不是生长促进，行动的生长激素在这海洋硬骨鱼。(c)2006爱思唯尔公司All rights reserved.
To evaluate a possible involvement of prolactin (PRL) in low-salinity tolerance of a marine puffertish Takifugu rubripes, or fugu, gene-expression profiles of PRL in the pituitary and PRL receptor (PRLR) in the osmoregulatory organs were investigated in fish exposed to 25%-dilute seawater (SW). Following transfer from full-strength (100%) SW to 25% SW, plasma osmolality and Na+ and Cl- levels were slightly decreased on day 1, which were restored on days 3 and 7. Expression levels of PRL mRNA in the pituitary was significantly increased in response to 25% SW transfer, which was in sharp contrast with a remarkable decrease in growth hormone (GH) mRNA levels. These profiles suggest that PRL and GH are involved in hyper- and hypoosmoregulation, respectively, as is the case with euryhaline teleosts. Expression levels of PRLR mRNA in the gill and intestine were not significantly different from the initial levels, whereas, PRLR mRNA expression in the kidney was significantly higher on day 7 than the initial levels. Although transfer to 25% SW did not affect the average size of Na+/K+-ATPase-immunoreactive chloride cells in the gills, both size and density of apical openings of chloride cells became significantly smaller after transfer to 25% SW. These findings suggest that the possible hypoosmotic action of PRL is mediated by PRLR expressed in the osmoregulatory organs, and that low-salinity tolerance of fugu may involve reduction of an ion-secreting function of gill chloride cells. To further evaluate long-term effects of the low-salinity environment on growth and osmoregulation, fugu were raised in 25% and 100% SW for a prolonged period of 8 weeks. They grew similarly in 25% and 100% SW, and there was no significant difference in body weight and standard length at any weekly sampling point. The plasma osmolality was maintained at about 345 mOsm/kg center dot H2O in both media, whereas the gill Na+/K+-ATPase activity was significantly lower in 25% SW than 100% SW. Gene expression of PRL in the pituitary was higher in 25% SW than in 100% SW; conversely, expression levels of GH were lower in 25% SW than in 100% SW. These findings support a hyperosmotic action of PRL and a hypoosmotic, rather than growth-promoting, action of GH in this marine teleost. (c) 2006 Elsevier Inc. All rights reserved.