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Cold Adaptation and it's Endocrine Control in Teleosts.

硬骨鱼的冷适应及其内分泌控制。

基本信息

批准号：
03640624
负责人：
OGAWA Mizuho
金额：
$ 0.58万
依托单位：
Saitama University
依托单位国家：
日本
项目类别：
Grant-in-Aid for General Scientific Research (C)
财政年份：
1991
资助国家：
日本
起止时间：
1991 至 1992
项目状态：
已结题

项目摘要

The seasonal variations of plasma osmolality and Na concentration in the plasma of the saffron cod were investigated. And with our previous data on the kidney structure and the pituitary immunohistochemistry, the mechanisms of cold adaptation for the saffron cod were discussed.Plasma osmolality was increased during the winter than during the summer. This high plasma osmolality of the winter fish may be due to the increased antifreeze glycoprotein content. Na concentration showed a higher value in the plasma of the winter fish than in those of the summer fish. The significance of such high Na concentration in the winter fish is need further study.In the fish collected during the summer, the positive immunoreactions with both growth hormone(GH) and prolactin(PRL) were remarkable than during the winter. However, there are no seasonal differences on the cross-sectional areas of GH- and PRL-secreting cells and their nuclei between the winter fish and the summer fish.It has been shown that an intact pituitary is necessary for the disappearance of antifreeze protein(AFP) from the plasma of the winter flounder during the summer(Fletcher et al.,'78). It is also evident recently that GH controls the concentration of AFP in the winter flounder reasoning its inhibitory effect of mRNA transcription in the liver, and PRL has no effect(Idler et al.,'89). In the teleost, however, it is known that PRL increases both urine flow and glomerular filtration rate involving an effect as the glomerular tuft is enlarged(Lam and leatherland,'69).These results reconfirmed the previous consideration(Ogawa et al.,'93) in which PRL may act possibly on clearing of antifreeze glycoprotein by increasing glomerular filtration during the summer.

本文研究了淡水鳕鱼血浆渗透压和血浆钠浓度的季节变化。并结合我们前期对肾脏结构和脑垂体免疫组化的研究结果，对鳕鱼冷适应的机制进行了初步探讨。这种高血浆渗透压的冬季鱼可能是由于增加抗冻糖蛋白含量。冬季鱼血浆中Na浓度高于夏季鱼。在夏季采集的鱼中，生长激素（GH）和催乳素（PRL）的免疫反应阳性率均显著高于冬季采集的鱼。然而，冬季鱼和夏季鱼的GH和PRL分泌细胞及其细胞核的横截面积没有季节性差异。已经表明，完整的脑垂体对于冬季比目鱼在夏季期间血浆中抗冻蛋白（AFP）的消失是必要的（弗莱彻等人，'78）。最近也很明显，GH控制着冬比目鱼中AFP的浓度，这是因为其对肝脏中mRNA转录的抑制作用，而PRL没有作用（Idler等人，'89）。然而，在硬骨鱼中，已知PRL增加尿流量和肾小球滤过率，涉及肾小球簇扩大的效应（Lam和leatherland，'69）。这些结果再次证实了先前的考虑（Ogawa等人，'93），其中PRL可能通过在夏季增加肾小球滤过而对抗冻糖蛋白的清除起作用。