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Endurance Exercise Training Enhances Local Sex Steroidogenesis in Skeletal Muscle.
MedLine Citation:
PMID:  21502890     Owner:  NLM     Status:  Publisher    
PURPOSE:: Endurance training improves skeletal muscular function including energy metabolism and structure. Sex steroid hormones partly contribute to the exercise-induced muscular adaptations. Recently, we demonstrated that skeletal muscle containes steroidgenic converting enzymes to synthesize sex steroid hormones and an acute endurance exercise activates local steroidogenesis in skeletal muscle. However, whether chronic endurance training leads to enhanced steroidogenesis in skeletal muscle is unknown. Here we examined changes in steroidogenic enzymes and sex steroid hormones in the skeletal muscle following chronic endurance exercise training. METHODS:: Eleven male rats were divided into 2 groups: sedentary (n=6), trained (n=5). Endurance training was performed on a treadmill (30 m/min, 30 min) at 5 days/wk for 12 weeks. The post-training harvesting were performed 48 h after the last exercise training. RESULTS:: The mRNA expressions of 3β-hydroxysteroid dehydrogenase (HSD), aromatase cytochrome P450 (P450arom) and 5α-reductase in the skeletal muscle of trained rats were significantly higher than that of sedentary rats (P < 0.05). The protein expressions of P450arom and 5α-reductase in the skeletal muscle of trained rats were also significantly higher than that of sedentary rats (P < 0.05). The muscular dihydrotestosterone (DHT) concentrations in the skeletal muscle of trained rats were significantly higher than that of sedentary rats (P 0.01), but no change in dehydroepiandrosterone (DHEA), total testosterone, free testosterone and estradiol. Furthermore, muscle weight corrected for BW of trained rats was moderately correlated with the level of muscular DHT concentration in trained rats (r = 0.41, P 0.05). CONCLUSION:: Endurance exercise training enhances the muscular DHT concentration through 5α-reductase in the skeletal muscle of rats, suggesting that local bioactive androgen metabolism may participate in exercise training-induced skeletal muscular adaptation.
Katsuji Aizawa; Motoyuki Iemitsu; Seiji Maeda; Noboru Mesaki; Takashi Ushida; Takayuki Akimoto
Publication Detail:
Type:  JOURNAL ARTICLE     Date:  2011-4-14
Journal Detail:
Title:  Medicine and science in sports and exercise     Volume:  -     ISSN:  1530-0315     ISO Abbreviation:  -     Publication Date:  2011 Apr 
Date Detail:
Created Date:  2011-4-19     Completed Date:  -     Revised Date:  -    
Medline Journal Info:
Nlm Unique ID:  8005433     Medline TA:  Med Sci Sports Exerc     Country:  -    
Other Details:
Languages:  ENG     Pagination:  -     Citation Subset:  -    
1 Laboratory of Regenerative Medical Engineering, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan; 2 Ritsumeikan University Faculty of Sport and Health Science, Shiga, Japan; 3 University of Tsukuba, Tsukuba, Japan; 4 Tekikyo Heisei University, Ichihara, Japan.
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