Co-expression of IGF-1 family members with myogenic regulatory factors following acut

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J Physiol. 2008 Sep 25;
McKay BR, O'Reilly CE, Phillips SM, Tarnopolsky MA, Parise G
Muscle regeneration following injury is dependant on the ability of muscle satellite cells to activate, proliferate and fuse with damaged fibers. This process is controlled by the myogenic regulatory factors (MRF). Little is known about the temporal relation of the MRF to the expression of known myogenic growth factors (i.e. IGF-1) in humans following muscle damage. Eight subjects (20.6+/-2.1y; 81.4+/-9.8kg) performed 300 lengthening contractions (180 degrees .s-1) of their knee extensors in one leg on a dynamometer. Blood and muscle samples were collected before and at 4 (T4), 24 (T24), 72 (T72), and 120 hours (T120) post-exercise. Mechano growth factor (MGF), IGF-1Ea, and IGF-1Eb mRNA were quantified. Serum IGF-1 did not change over the post-exercise time-course. IGF-1Ea and IGF-1Eb mRNA increased ~4-6 fold by T72 (p