Munakata Arimune, Amano Masafumi, Ikuta Kazumasa, Kitamura Shoji, Aida Katsumi
Department of Biology, Miyagi University of Education, Sendai, Miyagi 980-0845, Japan.
Gen Comp Endocrinol. 2007 Jan 1;150(1):12-7. doi: 10.1016/j.ygcen.2006.07.009. Epub 2006 Sep 22.
The effects of ovine growth hormone (oGH) and cortisol on downstream migratory behavior in yearling (1(+)) smolts and underyearling (0(+)) parr of masu salmon, Oncorhynchus masou, were examined during the downstream migratory period in spring using artificial raceways. In May, each of 22 1(+) smolts and 0(+) parr were implanted with cholesterol pellets containing 250 microg of oGH and/or 2 mg of cortisol. Their downstream migratory behavior was subsequently observed in artificial raceways, along with control groups 4-23 days after implantation. In 1(+) smolts, the frequency of downstream migratory behavior was 23%, 18%, 72%, and 82% in the control, oGH, cortisol, and oGH+cortisol-treated groups, respectively. The frequency was significantly higher in the cortisol and oGH+cortisol-treated groups than in the control and oGH-treated groups. In 0(+) parr, the frequency of downstream migratory behavior in the cortisol (82%) and cortisol+oGH-treated (90%) groups was significantly higher than in the control (18%) and oGH-treated (0%) groups. These results indicate that cortisol is an important endocrine factor inducing downstream migratory behavior in both 1(+) smolt and 0(+) parr of masu salmon.
在春季的下游洄游期，利用人工养殖水道，研究了绵羊生长激素（oGH）和皮质醇对马苏大麻哈鱼（Oncorhynchus masou）一岁龄（1(+)）稚鱼和零岁龄（0(+)）幼鱼下游洄游行为的影响。5月，给22尾1(+)稚鱼和0(+)幼鱼分别植入含有250微克oGH和/或2毫克皮质醇的胆固醇微丸。植入后4 - 23天，在人工养殖水道中观察它们的下游洄游行为，同时设置对照组。在1(+)稚鱼中，对照组、oGH处理组、皮质醇处理组和oGH +皮质醇处理组的下游洄游行为频率分别为23%、18%、72%和82%。皮质醇处理组和oGH +皮质醇处理组的频率显著高于对照组和oGH处理组。在0(+)幼鱼中，皮质醇处理组（82%）和皮质醇 + oGH处理组（90%）的下游洄游行为频率显著高于对照组（18%）和oGH处理组（0%）。这些结果表明，皮质醇是诱导马苏大麻哈鱼1(+)稚鱼和0(+)幼鱼下游洄游行为的重要内分泌因子。
