Miwa S, Inui Y
Gen Comp Endocrinol. 1985 Jun;58(3):436-42. doi: 10.1016/0016-6480(85)90116-9.
In a study of the hormonal control of salmon smoltification, L-thyroxine (T4; 200 ppm in diet), ovine growth hormone (oGH; 2 micrograms/g intramuscular injection weekly), or a combination of these hormones was administered to underyearling amago salmon parr for 72 days. Administration of both T4 + oGH remarkably stimulated growth of the fish. All hormone treatments caused body silvering of the fish. The body silvering was the greatest in the group treated with T4 + oGH. Both T4 + oGH and oGH increased survival rate of the fish in 32% seawater, and kept plasma osmolarity and plasma sodium concentration lower than those of T4-treated and control groups in 27% seawater. Significant elevation of gill Na+, K+-ATPase activity was found in T4 + oGH-treated fish. On the other hand, T4 by itself did not affect the seawater tolerance of the fish. These findings suggest that GH or synergistic action of GH and T4 plays an important role in seawater adaptation during smoltification of amago salmon.
在一项关于鲑鱼幼鱼化激素控制的研究中，给当年生的秋鲑幼鱼投喂含L-甲状腺素（T4；饲料中含量为200 ppm）、羊生长激素（oGH；每周肌肉注射2微克/克）或这两种激素的组合，持续72天。同时投喂T4 + oGH显著刺激了鱼的生长。所有激素处理都导致鱼体出现银色。在T4 + oGH处理组中，鱼体银色最为明显。T4 + oGH和oGH均提高了鱼在32%海水中的存活率，并使血浆渗透压和血浆钠浓度低于T4处理组和对照组在27%海水中的水平。在T4 + oGH处理的鱼中，鳃Na +，K + -ATP酶活性显著升高。另一方面，单独的T4对鱼的海水耐受性没有影响。这些发现表明，生长激素或生长激素与T4的协同作用在秋鲑幼鱼化过程中的海水适应中起着重要作用。
