title: Acute exercise activates local bioactive androgen metabolism in skeletal muscle.
abstract: Androgens, such as testosterone, play important roles in regulation of diverse physiological process of target tissues. Recently, we reported that steroidogenic enzymes exist in skeletal muscle and regulate local production of testosterone in response to exercise. Testosterone is transformed into a bioactive androgen metabolite, dihydrotestosterone (DHT) by 5alpha-reductase. However, it is unclear whether exercise stimulates local bioactive androgen metabolism in the skeletal muscle in both sexes. In the present study, we examined sex differences in the levels of dehydroepiandrosterone (DHEA), free testosterone, DHT, and steroidogenesis-related enzymes 5alpha-reductase and androgen receptor (AR) in rat's skeletal muscle before and after a single bout of exercise. Basal muscular free testosterone and DHT levels were higher in males than females, whereas the levels of DHEA did not differ between the sexes. Muscular DHEA, free testosterone, and DHT levels were increased in both sexes after the exercise. There were no differences of 5alpha-reductase and AR transcripts and proteins between the sexes, and the expression of 5alpha-reductase was significantly increased in both sexes after the exercise. Finally, the expression of AR was significantly higher in female rats, but not in males after the exercise. These data suggest that acute exercise enhances the local bioactive androgen metabolism in the skeletal muscle of both sexes.
authors.affiliation: Laboratory of Regenerative Medical Engineering, Center for Disease Biology and Integrative Medicine, Graduate School of Medicine, The University of Tokyo, Tokyo, Japan.
authors.forename: Katsuji
authors.initials: K
authors.lastname: Aizawa
authors.forename: Motoyuki
authors.initials: M
authors.lastname: Iemitsu
authors.forename: Seiji
authors.initials: S
authors.lastname: Maeda
authors.forename: Takeshi
authors.initials: T
authors.lastname: Otsuki
authors.forename: Koji
authors.initials: K
authors.lastname: Sato
authors.forename: Takashi
authors.initials: T
authors.lastname: Ushida
authors.forename: Noboru
authors.initials: N
authors.lastname: Mesaki
authors.forename: Takayuki
authors.initials: T
authors.lastname: Akimoto
mesh_terms: D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase / Q000235:genetics / Q000378:metabolism; D000728:Androgens / Q000378:metabolism*; D000818:Animals; D003687:Dehydroepiandrosterone / Q000378:metabolism; D013196:Dihydrotestosterone / Q000378:metabolism; D005260:Female; D008297:Male; D018482:Muscle, Skeletal / Q000378:metabolism*; D010805:Physical Conditioning, Animal / Q000502:physiology*; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D011944:Receptors, Androgen / Q000235:genetics / Q000378:metabolism; D013739:Testosterone / Q000378:metabolism
chemical_list: D000728:Androgens; D011944:Receptors, Androgen; D013196:Dihydrotestosterone; D013739:Testosterone; D003687:Dehydroepiandrosterone; D013741:3-Oxo-5-alpha-Steroid 4-Dehydrogenase