S. D. McCormick 2011 <p><span>Hormones are critical to the physiological alterations necessary for ion&nbsp;homeostasis&nbsp;when fish move between freshwater and&nbsp;seawater.&nbsp;Cortisol&nbsp;promotes seawater&nbsp;acclimation&nbsp;through differentiation of salt-secreting mitochondrion-rich cells and&nbsp;ion transport&nbsp;proteins in the&nbsp;gill. The growth hormone/insulin-like growth factor I axis is also important in seawater acclimation and acts in synergy with cortisol.&nbsp;</span>Prolactin<span>&nbsp;(PRL) is important in freshwater acclimation through regulation of&nbsp;ion and water permeability&nbsp;in the gill, gut, and kidney. Cortisol also promotes ion uptake and may interact with PRL during freshwater acclimation. For many species of fish,&nbsp;growth hormone&nbsp;promotes acclimation to seawater, PRL promotes acclimation to freshwater, and cortisol interacts with both hormones, thus having a dual osmoregulatory function.</span></p> application/pdf 10.1016/B978-0-12-374553-8.00212-4 en Elsevier The hormonal control of osmoregulation in teleost fish article