Expression of myogenic regulatory factors in normal and dystrophic mice: Effects of IGF-1 treatment

H. H. Hsu, M. M. Zdanowicz, V. R. Agarwal, P. W. Speiser

Research output: Contribution to journalArticlepeer-review

18 Scopus citations


Myogenic regulatory factors (MRFs) promote differentiation of muscle cells from fibroblasts and are induced by insulin-like growth factor I (IGF- 1). Prior studies have shown synthesis of new muscle protein and improved muscle morphology when mature dy mice with muscular dystrophy are treated with IGF-1. We investigated whether these salutary effects of IGF-1 might be attributable to stimulation of MRFs. Male dy (129ReJ) mice and controls (129J) were assigned to IGF-1 treatment (10 μg twice daily) or nontreatment at about 5 weeks of life and sacrificed 6 weeks later. RNA was extracted from skeletal muscles, reverse transcribed, and amplified by polymerase chain reaction (PCR) using primers specific for each MRF. Competitive PCR was performed to quantify MyoD expression in response to IGF-1 treatment. Transcripts for myf-5, MRF4, and myogenin were detected in both control and dy mouse muscles; no apparent differences were observed between treatment groups. Quantitative analysis of transcripts for MyoD indicated no significant basal differences between control and dy mice. There was, however, significantly higher MyoD expression in the dy group, and a trend toward significance in the control group, following IGF-1 treatment. These data suggest that IGF-1 exerts its in vivo effects in postembryonal muscle by stimulating MRFs.

Original languageEnglish (US)
Pages (from-to)142-148
Number of pages7
JournalBiochemical and Molecular Medicine
Issue number2
StatePublished - Apr 1997
Externally publishedYes

ASJC Scopus subject areas

  • Biochemistry


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