IGF-i/PI3K/AKT and IGF-I/MAPK/ERK pathways in vivo in skeletal muscle are regulated by nutrition and contribute to somatic growth in the fine flounder

Eduardo N. Fuentes, Björn Thrandur Björnsson, Juan Antonio Valdés, Ingibjörg Eir Einarsdottir, Belen Lorca, Marco Alvarez, Alfredo Molina

Research output: Contribution to journalArticlepeer-review

109 Citations (Scopus)

Abstract

The insulin-like growth factor-I (IGF-I) is a key regulator of skeletal muscle growth in vertebrates, promoting mitogenic and anabolic effects through the activation of the MAPK/ERK and the PI3K/Akt signaling pathways. Nutrition also affects skeletal muscle growth, activating intracellular pathways and inducing protein synthesis and accretion. Thus, both hormonal and nutritional signaling regulate muscle mass. In this context, plasma IGF-I levels and the activation of both pathways in response to food were evaluated in the fine flounder using fasting and refeeding trials. The present study describes for the first time in a nonmammalian species that the MAPK/ERK and PI3K/Akt are activated by exogenous circulating IGF-I, as well as showing that the MAPK/ERK pathway activation is modulated by the nutritional status. Also, these results show that there is a time-dependent regulation of IGF-I plasma levels and its signaling pathways in muscle. Together, these results suggest that the nutritionally managed IGF-I could be regulating the activation of the MAPK/ERK and the PI3K/ Akt signaling pathways differentially according to the nutritional status, triggering different effects in growth parameters and therefore contributing to somatic growth in fish. This study contributes to the understanding of the nutrient regulation of IGF-I and its signaling pathways in skeletal muscle growth in nonmammalian species, therefore providing insight concerning the events controlling somatic growth in vertebrates.

Original languageEnglish
Pages (from-to)1532-1542
Number of pages11
JournalAmerican Journal of Physiology - Regulatory Integrative and Comparative Physiology
Volume300
Issue number6
DOIs
Publication statusPublished - Jun 2011

Keywords

  • Fasting
  • Fish growth
  • Pathway activation
  • Refeeding

ASJC Scopus subject areas

  • Physiology
  • Physiology (medical)

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