The growth hormone (Gh)/insulin-like growth-factor (Igf)/Igf binding protein (Igfbp) system regulates growth and osmoregulation in salmonid fishes, but how this system interacts with other endocrine systems is largely unknown. Given the well-documented consequences of mounting a glucocorticoid stress response on growth, we hypothesized that cortisol inhibits anabolic processes by modulating the expression of hepatic igfbp mRNAs. Atlantic salmon (Salmo salar) parr were implanted intraperitoneally with cortisol implants (0, 10, and 40 μg g⁻¹ body weight) and sampled after 3 or 14 days. Cortisol elicited a dose-dependent reduction in specific growth rate (SGR) after 14 days. While plasma Gh and Igf1 levels were unchanged, hepatic igf1 mRNA was diminished and hepatic igfbp1b1 and -1b2 were stimulated by the high cortisol dose. Plasma Igf1 was positively correlated with SGR at 14 days. Hepatic gh receptor (ghr), igfbp1a, -2a, -2b1, and -2b2 levels were not impacted by cortisol. Muscle igf2, but not igf1 or ghr, levels were stimulated at 3 days by the high cortisol dose. As both cortisol and the Gh/Igf axis promote seawater (SW) tolerance, and particular igfbps respond to SW exposure, we also assessed whether cortisol coordinates the expression of branchial igfbps and genes associated with ion transport. Cortisol stimulated branchial igfbp5b2 levels in parallel with Na⁺/K⁺-ATPase (NKA) activity and nka-α1b, Na⁺/K⁺/2Cl^--cotransporter 1 (nkcc1), and cystic fibrosis transmembrane regulator 1 (cftr1) mRNA levels. The collective results indicate that cortisol modulates the growth of juvenile salmon via the regulation of hepatic igfbp1s whereas no clear links between cortisol and branchial igfbps previously shown to be salinity-responsive could be established.

生长激素（Gh）/胰岛素样生长因子（Igf）/ Igf结合蛋白（Igfbp）系统调节鲑鱼的生长和渗透调节作用，但该系统如何与其他内分泌系统相互作用尚不清楚。鉴于有文献记载的糖皮质激素应激反应对生长的影响，我们假设皮质醇通过调节肝igfbp mRNA的表达来抑制合成代谢过程。将大西洋鲑（Salmo salar）parr腹膜内植入皮质醇植入物（0、10和40μgg ^-1体重），并在3或14天后取样。皮质醇在14天后引起比生长速率（SGR）的剂量依赖性降低。血浆Gh和Igf1水平不变，而肝igf1mRNA减少，高剂量皮质醇刺激肝igfbp1b1和-1b2。血浆Igf1在14天时与SGR正相关。肝gh受体（ghr），igfbp1a，-2a，-2b1和-2b2的水平不受皮质醇的影响。在第3天，高皮质醇剂量刺激了igf2肌肉水平，而不是igf1或ghr水平。由于皮质醇和Gh / Igf轴均促进海水（SW）耐受性，并且特定的igfbps对SW暴露有响应，因此我们还评估了皮质醇是否协调了小肠的表达igfbps和与离子迁移相关的基因。皮质醇刺激鳃igfbp5b2在用Na平行水平⁺ / K ⁺ -ATP酶（NKA）活性和NKA-α1B，钠⁺ / K ⁺ / 2CL ^- -cotransporter 1（NKCC1）和囊性纤维化跨膜调节1（cftr1）mRNA水平。总体结果表明，皮质醇通过肝igfbp1s的调节来调节鲑鱼的生长，而皮质醇与分支igfbps之间没有明确的联系 可以证明以前显示出对盐分敏感。