Young G, Björnsson B T, Prunet P, Lin R J, Bern H A
Department of Zoology and Cancer Research Laboratory, University of California, Berkeley 94720.
Gen Comp Endocrinol. 1989 Jun;74(3):335-45. doi: 10.1016/s0016-6480(89)80029-2.
The status of circulating growth hormone and prolactin during the parr-smolt transformation and during seawater adaptation of coho salmon (Oncorhynchus kisutch) was investigated in relation to changes in plasma levels of thyroxine, triiodothyronine, and cortisol, and in hypoosmoregulatory ability. Sampling (biweekly or monthly) occurred between early February and October. When peak hypoosmoregulatory ability was achieved (mid-April), one group of fish was acclimated to seawater over a period of 18 hr and was sampled 1, 3, and 7 days after the introduction of fish to seawater and biweekly thereafter. Plasma prolactin levels rose steadily from the first sampling date to a peak of 15 ng/ml in early April, declined rapidly, and remained low until June when a second increase occurred. Prolactin declined to 2 ng/ml within 1 day of the beginning of seawater adaptation. Growth hormone increased twofold from February to late March, and achieved plateau levels of 20 ng/ml in the period from mid-April to July and then gradually declined to 10 ng/ml in September and October. Plasma levels of growth hormone in seawater-acclimated fish were similar to those of freshwater coho, but with larger fluctuations; no increase was apparent during the first week of seawater acclimation. Plasma cortisol and plasma triiodothyronine increased at the same time as plasma growth hormone; increases in plasma thyroxine occurred later. In general, both growth hormone and cortisol levels were elevated when hypoosmoregulatory ability was high. Conversely, prolactin levels generally showed a negative relationship with hypoosmoregulatory ability.
研究了银大麻哈鱼（Oncorhynchus kisutch）在幼鲑-稚鲑转化阶段以及海水适应过程中循环生长激素和催乳素的状态，及其与甲状腺素、三碘甲状腺原氨酸和皮质醇血浆水平变化以及低渗调节能力变化的关系。采样时间（每两周或每月一次）为2月初至10月。当达到最大低渗调节能力时（4月中旬），一组鱼在18小时内适应海水，并在放入海水后的第1、3和7天以及此后每两周采样一次。血浆催乳素水平从首次采样日期开始稳步上升，4月初达到15 ng/ml的峰值，随后迅速下降，并在6月前一直保持在低水平，6月出现第二次升高。在海水适应开始后的1天内，催乳素降至2 ng/ml。生长激素从2月到3月下旬增加了两倍，在4月中旬至7月期间达到20 ng/ml的稳定水平，然后在9月和10月逐渐降至10 ng/ml。适应海水的鱼的血浆生长激素水平与淡水银大麻哈鱼相似，但波动更大；在海水适应的第一周内没有明显增加。血浆皮质醇和血浆三碘甲状腺原氨酸与血浆生长激素同时增加；血浆甲状腺素的增加出现较晚。一般来说，当低渗调节能力较高时，生长激素和皮质醇水平都会升高。相反，催乳素水平通常与低渗调节能力呈负相关。
