Hepatic insulin-like growth-factor binding protein (igfbp) responses to food restriction in Atlantic salmon smolts
| Autor: | Chelsea K. Fujimoto, Silas K. Phipps-Costin, Björn Thrandur Björnsson, Ingibjörg Eir Einarsdottir, Amy M. Regish, Jason P. Breves, Stephen D. McCormick |
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| Rok vydání: | 2016 |
| Předmět: |
0301 basic medicine
endocrine system medicine.medical_specialty medicine.medical_treatment Salmo salar Insulins Biology DNA-binding protein Insulin-like growth factor-binding protein 03 medical and health sciences Insulin-like growth factor Endocrinology Insulin-Like Growth Factor II Internal medicine medicine Animals Salmo Insulin-Like Growth Factor I Smoltification Caloric Restriction Life Cycle Stages Catabolism Transporter Fasting Salt Tolerance biology.organism_classification Insulin-Like Growth Factor Binding Proteins 030104 developmental biology Ion pump Liver Growth Hormone biology.protein Animal Science and Zoology Animal Migration Seasons Food Deprivation hormones hormone substitutes and hormone antagonists |
| Zdroj: | General and comparative endocrinology. 233 |
| ISSN: | 1095-6840 |
| Popis: | The growth hormone (Gh)/insulin-like growth-factor (Igf) system plays a central role in the regulation of growth in fishes. However, the roles of Igf binding proteins (Igfbps) in coordinating responses to food availability are unresolved, especially in anadromous fishes preparing for seaward migration. We assayed plasma Gh, Igf1, thyroid hormones and cortisol along with igfbp mRNA levels in fasted and fed Atlantic salmon (Salmo salar). Fish were fasted for 3 or 10days near the peak of smoltification (late April to early May). Fasting reduced plasma glucose by 3days and condition factor by 10days. Plasma Gh, cortisol, and thyroxine (T4) were not altered in response to fasting, whereas Igf1 and 3,5,3'-triiodo-l-thyronine (T3) were slightly higher and lower than controls, respectively. Hepatic igfbp1b1, -1b2, -2a, -2b1 and -2b2 mRNA levels were not responsive to fasting, but there were marked increases in igfbp1a1 following 3 and 10days of fasting. Fasting did not alter hepatic igf1 or igf2; however, muscle igf1 was diminished by 10days of fasting. There were no signs that fasting compromised branchial ionoregulatory functions, as indicated by unchanged Na(+)/K(+)-ATPase activity and ion pump/transporter mRNA levels. We conclude that dynamic hepatic igfbp1a1 and muscle igf1 expression participate in the modulation of Gh/Igf signaling in smolts undergoing catabolism. |
| Databáze: | OpenAIRE |
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