| Summary: | The growth performance of teleost fishes is largely controlled by the growth hormone (Gh)/insulin‐like growth‐factor (Igf) system. Furthermore, Igfs interact with an expanded suite of cognate binding proteins, termed Igf binding proteins (Igfbps), produced by key metabolic tissues such as liver and muscle. Igfbps modulate the biological activities of Igfs under various physiological situations, such as when a glucocorticoid stress response has been mounted. In juvenile Atlantic salmon ( Salmo salar ), we have previously identified two igfbp genes, namely igfbp1b1 and igfbp1b2 , that increase their expression in response to the endogenous glucocorticoid cortisol. These responses underlie, in part, the inhibition of anabolic processes known to occur in parallel with a glucocorticoid stress response. In the current study, we tested the hypothesis that the synthetic corticosteroid, prednisolone, may similarly inhibit anabolic processes by impacting the Gh/Igf/Igfbp network. We implanted Atlantic salmon parr with prednisolone (0, 2.5 and 25 μg/g body weight) or cortisol (25 μg/g) and sampled individuals after 14 days. We observed reduced growth rates (fork length) following treatment with the high dose of prednisolone (25 μg/g) and cortisol. We will report igfbp transcript levels in liver and skeletal muscle to resolve whether activities within the Igfbp network are modulated by prednisolone in juvenile Atlantic salmon. This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal .
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