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The Scientific World Journal
Volume 2013 (2013), Article ID 313605, 5 pages
Research Article

The Effect of Anabolic Steroid Administration on Passive Stretching-Induced Expression of Mechano-Growth Factor in Skeletal Muscle

1Department of Rehabilitation and Physical Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8506, Japan
2School of Medical Sciences, Faculty of Medicine, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8544, Japan

Received 25 June 2013; Accepted 25 July 2013

Academic Editors: H. Kagaya and S. Sonoda

Copyright © 2013 Satoshi Ikeda et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


Background. Stretching of skeletal muscle induces expression of the genes which encode myogenic transcription factors or muscle contractile proteins and results in muscle growth. Anabolic steroids are reported to strengthen muscles. We have previously studied the effects of muscle stretching on gene expression. Here, we studied the effect of a combination of passive stretching and the administration of an anabolic steroid on mRNA expression of a muscle growth factor, insulin-like growth factor-I autocrine variant, or mechano-growth factor (MGF). Methods. Twelve 8-week-old male Wistar rats were used. Metenolone was administered and passive repetitive dorsiflexion and plantar flexion of the ankle joint performed under deep anesthesia. After 24 h, the gastrocnemius muscles were removed and the mRNA expression of insulin-like growth factor-I autocrine variant was measured using quantitative real-time polymerase chain reaction. Results. Repetitive stretching in combination with metenolone, but not stretching alone, significantly increased MGF mRNA expression. Conclusion. Anabolic steroids enhance the effect of passive stretching on MGF expression in skeletal muscle.