title: Effects of sustained exercise on GH-IGFs axis in gilthead sea bream (Sparus aurata).
abstract: The endocrine system regulates growth mainly through the growth hormone (GH)/insulin-like growth factors (IGFs) axis and, although exercise promotes growth, little is known about its modulation of these factors. The aim of this work was to characterize the effects of 5 wk of moderate sustained swimming on the GH-IGFs axis in gilthead sea bream fingerlings. Plasma IGF-I/GH ratio and tissue gene expression of total IGF-I and three splice variants, IGF-II, three IGF binding proteins, two GH receptors, two IGF-I receptors, and the downstream molecules were analyzed. Fish under exercise (EX) grew more than control fish (CT), had a higher plasma IGF-I/GH ratio, and showed increased hepatic IGF-I expression (mainly IGF-Ia). Total IGF-I expression levels were similar in the anterior and caudal muscles; however, IGF-Ic expression increased with exercise, suggesting that this splice variant may be the most sensitive to mechanical action. Moreover, IGFBP-5b and IGF-II increased in the anterior and caudal muscles, respectively, supporting enhanced muscle growth. Furthermore, in EX fish, hepatic IGF-IRb was reduced together with both GHRs; GHR-II was also reduced in anterior muscle, while GHR-I showed higher expression in the two muscle regions, indicating tissue-dependent differences and responses to exercise. Exercise also increased gene and protein expression of target of rapamycin (TOR), suggesting enhanced muscle protein synthesis. Altogether, these data demonstrate that moderate sustained activity may be used to increase the plasma IGF-I/GH ratio and to potentiate growth in farmed gilthead sea bream, modulating the gene expression of different members of the GH-IGFs axis (i.e., IGF-Ic, IGF-II, IGFBP-5b, GHR-I, and TOR).
authors.affiliation: Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain;
authors.forename: Emilio J
authors.initials: EJ
authors.lastname: Vélez
authors.affiliation: Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain; Department of Fisheries Sciences, Faculty of Natural Resources, University of Tehran, Karaj, Iran;
authors.forename: Sheida
authors.initials: S
authors.lastname: Azizi
authors.affiliation: Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain;
authors.forename: Antonio
authors.initials: A
authors.lastname: Millán-Cubillo
authors.affiliation: Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain;
authors.forename: Jaume
authors.initials: J
authors.lastname: Fernández-Borràs
authors.affiliation: Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain;
authors.forename: Josefina
authors.initials: J
authors.lastname: Blasco
authors.affiliation: Departments of Biochemistry, and Molecular Biology and Medicine, The Howard Hughes Medical Institute, University of Chicago, Chicago, Illinois; and.
authors.forename: Shu Jin
authors.initials: SJ
authors.lastname: Chan
authors.affiliation: Nutrition and Fish Growth Endocrinology, Institute of Aquaculture Torre de la Sal, Consejo Superior de Investigaciones Científicas, Castellón, Spain.
authors.forename: Josep A
authors.initials: JA
authors.lastname: Calduch-Giner
authors.affiliation: Nutrition and Fish Growth Endocrinology, Institute of Aquaculture Torre de la Sal, Consejo Superior de Investigaciones Científicas, Castellón, Spain.
authors.forename: Jaume
authors.initials: J
authors.lastname: Pérez-Sánchez
authors.affiliation: Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain;
authors.forename: Isabel
authors.initials: I
authors.lastname: Navarro
authors.affiliation: Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain;
authors.forename: Encarnación
authors.identifier: http://orcid.org/0000-0002-0863-9728
authors.initials: E
authors.lastname: Capilla
authors.affiliation: Departament de Fisiologia i Immunologia, Facultat de Biologia, Universitat de Barcelona, Barcelona, Spain; jgutierrez@ub.edu.
authors.forename: Joaquim
authors.initials: J
authors.lastname: Gutiérrez
mesh_terms: D000818:Animals; D005786:Gene Expression Regulation / Q000235:genetics; D013006:Growth Hormone / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D018969:Insulin-Like Growth Factor Binding Proteins / Q000235:genetics / Q000378:metabolism; D007814:Larva; D008099:Liver / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D010805:Physical Conditioning, Animal / Q000502:physiology*; D005082:Physical Exertion / Q000502:physiology*; D021541:Sea Bream / Q000378:metabolism*; D013002:Somatomedins / Q000096:biosynthesis / Q000235:genetics / Q000502:physiology*; D013550:Swimming / Q000502:physiology
chemical_list: D018969:Insulin-Like Growth Factor Binding Proteins; D013002:Somatomedins; D013006:Growth Hormone
keywords: GH receptors; IGF binding proteins; IGF-I receptors; IGFs; TOR; growth hormone; swimming