Insulin-like growth factor immunoreactivity increases in muscle after acute eccentric contractions.
The purpose of the study was to note whether insulin-like growth factor (IGF) immunoreactivity increased after eccentric contractions. IGF immunoreactivity in the rat tibialis anterior muscle was measured on 5 successive days (4-5 rats/group, n = 28) after an acute bout of 192 eccentric contractions elicited by electrical stimulation. The muscle tissue sections were immunocytochemically processed with rabbit anti-human IGF-I serum. Immunoreactivity was analyzed with videomicroscopy and computer-aided image processing. Four days after eccentric contractions, IGF immunoreactivity was significantly higher than control [0.081 +/- 0.073 (SD) absorbance at 480 nm vs. 0.026 +/- 0.018; P < 0.05]. The increases in IGF-I immunoreactivity were mostly within the muscle fibers. These results suggest that an acute bout of eccentric exercise increases IGF-I immunoreactivity in rat type II muscle 4 days postexercise.
Yan
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Department of Physiology and Cell Biology, University of Texas Medical School, Houston 77225.
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D000818:Animals; D005260:Female; D007091:Image Processing, Computer-Assisted; D007150:Immunohistochemistry; D007334:Insulin-Like Growth Factor I / Q000276:immunology / Q000378:metabolism*; D009119:Muscle Contraction / Q000502:physiology; D009124:Muscle Proteins / Q000096:biosynthesis; D009132:Muscles / Q000033:anatomy & histology / Q000378:metabolism*; D005082:Physical Exertion / Q000502:physiology*; D051381:Rats; D017207:Rats, Sprague-Dawley
D009124:Muscle Proteins; D007334:Insulin-Like Growth Factor I