Effect of training and growth hormone suppression on insulin-like growth factor I mRNA in young rats

S. Zanconato, D. Y. Moromisato, M. Y. Moromisato, J. Woods, J. A. Brasel, D. Leroith, C. T. Roberts, D. M. Cooper

    Research output: Contribution to journalArticle

    65 Scopus citations

    Abstract

    The growth hormone (GH)-insulin-like growth factor I (IGF-I) axis plays a role in the adaptation to exercise training, but IGF-I gene expression in response to exercise training and GH suppression has not been studied. Twenty female rats underwent a 4-wk treadmill training program begun in the prepubertal period (day 14 of life). In 10 of the training rats, GH production was suppressed by anti-GH-releasing hormone antibodies (GH suppressed). IGF-I mRNA and protein levels were measured in liver and hindlimb skeletal muscle. GH suppression reduced IGF-I mRNA expression in the liver to a much greater extent than in the muscle. In the GH control rats, training induced significant increases in hepatic exon 1-derived IGF-I mRNA (mean increase 30%; P < 0.05) and muscle exon 2-derived mRNA (mean increase 35%; P < 0.05). In the GH-suppressed rats, only muscle exon 1-derived transcripts were significantly increased by training (55%; P < 0.05) and this was associated with a significant increase in muscle IGF-I protein levels (P < 0.05). We speculate that the anabolic response to training may involve both GH-dependent increases in IGF-I mRNA in the liver and GH-independent increases in the muscle.

    Original languageEnglish (US)
    Pages (from-to)2204-2209
    Number of pages6
    JournalJournal of Applied Physiology
    Volume76
    Issue number5
    DOIs
    StatePublished - Jan 1 1994

    Keywords

    • hindlimb muscle
    • insulin-like growth factor I protein level
    • liver

    ASJC Scopus subject areas

    • Physiology
    • Physiology (medical)

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    Zanconato, S., Moromisato, D. Y., Moromisato, M. Y., Woods, J., Brasel, J. A., Leroith, D., Roberts, C. T., & Cooper, D. M. (1994). Effect of training and growth hormone suppression on insulin-like growth factor I mRNA in young rats. Journal of Applied Physiology, 76(5), 2204-2209. https://doi.org/10.1152/jappl.1994.76.5.2204