TY - JOUR T1 - The Role of the Insulin-like Growth Factor 1 (IGF-1) in Skeletal Muscle Physiology JF - In Vivo JO - In Vivo SP - 45 LP - 54 VL - 21 IS - 1 AU - ANASTASSIOS PHILIPPOU AU - MARIA MARIDAKI AU - ANTONIS HALAPAS AU - MICHAEL KOUTSILIERIS Y1 - 2007/01/01 UR - http://iv.iiarjournals.org/content/21/1/45.abstract N2 - The human insulin-like growth factor-1 (IGF-1) gene gives rise to multiple, heterogeneous mRNA transcripts through a combination of multiple transcription initiation sites, alternative splicing and different polyadenylation signals. These IGF-1 mRNA transcripts code different isoforms of the precursor peptide of IGF-1 (IGF-1Ea, IGF-1Eb and IGF-1Ec or MGF in human skeletal muscle), which also undergo post-translational modification. There is increasing interest in differential expression and implication of IGF-1 isoforms in the regulation of muscle fiber regeneration and hypertrophy following mechanical overloading and damage. The identification of a locally expressed, loading- or damage-sensitive IGF-1 isoform in skeletal muscle was one of the most attractive developments in the context of the autocrine/ paracrine actions of IGF-1. The concept that the competing processes of cellular proliferation and differentiation and the increased protein synthesis required for muscle repair or hypertrophic adaptation are regulated by a differential expression and by distinct roles of IGF-1 isoforms is discussed in the present review. Copyright © 2007 International Institute of Anticancer Research (Dr. John G. Delinassios), All rights reserved ER -