Plasma and urine levels of electrolytes, urea and steroid hormones involved in osmoregulation of cetaceans
Plasma and urine levels of electrolytes, urea and steroid hormones involved in osmoregulation of cetaceans
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DOI：
10.2108/zsj.22.1245
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发表时间：
2005-11-01
影响因子：
0.9
通讯作者：
Urano, Akihisa
中科院分区：
文献类型：
--
作者：
Birukawa, Naoko;Ando, Hironori;Urano, Akihisa
鲸类动物通过适当发育的渗透调节能力，很好地适应了高渗环境。这里的一个问题是它们如何调节海洋栖息地的水和矿物质平衡。在本研究中，我们测定了与渗透调节有关的各种化学物质的血液和尿液水平，并将它们与偶蹄动物的水平进行了比较，并对鲸鱼的数值进行了表征。对普通小须鲸（Balaenoptera acutorostrata）、须鲸（B. borealis）、布氏鲸（B. brydei）和抹香鲸（Physeter macrocephalus）的齿鲸（Physeter macrocephalus）的血液和尿液样本进行渗透压、主要电解质、尿素、类固醇激素和葡萄糖的分析。鲸类动物的尿液渗透压和Na+浓度明显高于牛。此外，鲸类动物血浆尿素含量是牛的5 ~ 11倍，尿液尿素含量是牛的2 ~ 4倍。鲸类动物和牛的血浆皮质激素浓度没有显著差异。本研究结果表明，渗透调节参数似乎不受生殖阶段和性类固醇激素的影响。须鲸血浆和尿液中的尿素浓度高于抹香鲸，表明它们的渗透调节机制可能与它们的摄食习惯有关。目前的研究结果表明，鲸类动物具有独特的渗透调节机制，通过排泄高渗尿液来维持海洋栖息地的流体稳态。
Cetaceans are well adapted to their hyperosmotic environment by properly developed osmoregulatory ability. A question here is how they regulate water and mineral balances in marine habitats. In the present study, we determined blood and urine levels of various chemicals involved in osmoregulation, compared them with those in artiodactyls, and characterized the values in the whales. Blood and urine samples obtained from baleen whales of common minke (Balaenoptera acutorostrata), sei (B. borealis), and Bryde's whales (B. brydei), and toothed whales of sperm whales (Physeter macrocephalus) were analyzed for osmolality, major electrolytes, urea, steroid hormones and glucose. The urine osmolality and Na+ concentrations in the cetaceans were much higher than those in the cattle. Furthermore, the cetaceans had 5 to 11-fold urea in plasma than the cattle, and 2 to 4-fold urea in urine. There were no significant difference in the plasma concentrations of corticosteroids between the cetaceans and the cattle. The present results indicate that the osmoregulatory parameters seem to be not affected by the reproductive stage and sex steroid hormones. The concentrations of urea in plasma and urine of the baleen whales were higher than those of the sperm whales, indicating a possibility that their osmoregulatory mechanisms may be correlated to their feeding habits. The present results suggest that cetaceans have unique osmoregulatory mechanisms by which they excrete strongly hypertonic urine to maintain fluid homeostasis in marine habitats.