Rydevik M, Borg B, Haux C, Kawauchi H, Björnsson B T
Department of Zoology, University of Stockholm, Sweden.
Gen Comp Endocrinol. 1990 Oct;80(1):9-15. doi: 10.1016/0016-6480(90)90142-9.
At the time of smoltification in May, smolts and sexually mature male parr were transferred to seawater (25% salinity) and sampled after 6 and 24 hr. Plasma levels of growth hormone (GH) were measured by radioimmunoassay. There was no difference in GH levels between smolts and mature parr in fresh water. GH levels did not change during exposure of smolts to seawater. In the mature male parr, plasma GH levels increased after 24 hr, when the levels were almost five times those of the freshwater controls. In the mature male parr, there was an increase in plasma osmolality, sodium, and magnesium after 24 hr in seawater; magnesium also increased after 6 hr. The levels of potassium and calcium did not change in either immature parr or mature male parr. The increase in plasma GH levels in the mature parr in seawater may be part of a mechanism to increase hypoosmoregulatory ability in fish not ready for seawater entry.
在5月银化时，银化幼鱼和性成熟雄幼鲑被转移到海水（盐度25%）中，并在6小时和24小时后取样。通过放射免疫测定法测量生长激素（GH）的血浆水平。在淡水中，银化幼鱼和成熟雄幼鲑的GH水平没有差异。银化幼鱼暴露于海水中期间，GH水平没有变化。在成熟雄幼鲑中，24小时后血浆GH水平升高，此时该水平几乎是淡水对照组的五倍。在成熟雄幼鲑中，海水暴露24小时后血浆渗透压、钠和镁增加；镁在6小时后也增加。未成熟雄幼鲑或成熟雄幼鲑的钾和钙水平均未变化。海水中成熟雄幼鲑血浆GH水平的升高可能是一种机制的一部分，该机制用于提高尚未准备好进入海水的鱼类的低渗调节能力。
