The effect of anabolic steroid administration on passive stretching-induced expression of mechano-growth factor in skeletal muscle.
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.


CONCLUSIONS
Anabolic steroids enhance the effect of passive stretching on MGF expression in skeletal muscle.
Department of Rehabilitation and Physical Medicine, Graduate School of Medical and Dental Sciences, Kagoshima University, 8-35-1 Sakuragaoka, Kagoshima 890-8506, Japan.
Satoshi
S
Ikeda
Yurie
Y
Kamikawa
Akihiko
A
Ohwatashi
Katsuhiro
K
Harada
Akira
A
Yoshida
D045930:Anabolic Agents / Q000494:pharmacology*; D000818:Animals; D007334:Insulin-Like Growth Factor I / Q000235:genetics / Q000378:metabolism*; D008297:Male; D040542:Mechanotransduction, Cellular / Q000187:drug effects*; D008710:Methenolone / Q000494:pharmacology*; D052580:Muscle Stretching Exercises; D018482:Muscle, Skeletal / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D060888:Real-Time Polymerase Chain Reaction
D045930:Anabolic Agents; D012333:RNA, Messenger; C519382:mechano-growth factor, rat; D007334:Insulin-Like Growth Factor I; D008710:Methenolone