Upper-body resistance exercise augments vastus lateralis androgen receptor-DNA binding and canonical Wnt/β-catenin signaling compared to lower-body resistance exercise in resistance-trained men without an acute increase in serum testosterone.
The purpose of the study was to determine the effect of single bouts of lower-body (LB) and upper- and lower-body (ULB) resistance exercise on serum testosterone concentrations and the effects on muscle testosterone, dihydrotestosterone (DHT), androgen receptor (AR) protein content, and AR-DNA binding. A secondary purpose was to determine the effects on serum wingless-type MMTV integration site (Wnt4) levels and skeletal muscle β-catenin content. In a randomized cross-over design, exercise bouts consisted of a LB and ULB protocol, and each bout was separated by 1 week. Blood and muscle samples were obtained before exercise and 3 and 24h post-exercise; blood samples were also obtained at 0.5, 1, and 2 h post-exercise. Statistical analyses were performed by separate two-way factorial analyses of variance (ANOVA) with repeated measures. No significant differences from baseline were observed in serum total and free testosterone and skeletal muscle testosterone and DHT with either protocol (p>0.05). AR protein was significantly increased at 3 h post-exercise and decreased at 24 h post-exercise for ULB, whereas AR-DNA binding was significantly increased at 3 and 24h post-exercise (p<0.05). In response to ULB, serum Wnt4 was significantly increased at 0.5, 1, and 2 h post-exercise (p<0.05) and β-catenin was significantly increased at 3 and 24 h post-exercise (p<0.05). It was concluded that, despite a lack of increase in serum testosterone and muscle androgen concentrations from either mode of resistance exercise, ULB resistance exercise increased Wnt4/β-catenin signaling and AR-DNA binding.
Department of Health, Physical Education, and Leisure Studies, University of South Alabama, Mobile, AL 36688, USA.
Mike
M
Spillane
Department of Health, Physical Education, and Leisure Studies, University of South Alabama, Mobile, AL 36688, USA.
Neil
N
Schwarz
Exercise and Biochemical Nutrition Lab, Department of Health, Human Performance, and Recreation, Baylor University, Waco, TX 76798, USA. Electronic address: darryn_willoughby@baylor.edu.
Darryn S
DS
Willoughby
D000328:Adult; D018592:Cross-Over Studies; D015444:Exercise / Q000502:physiology*; D006801:Humans; D008297:Male; D052097:Quadriceps Muscle / Q000378:metabolism*; D011944:Receptors, Androgen / Q000378:metabolism*; D013739:Testosterone / Q000097:blood*; D013997:Time Factors; D060449:Wnt Signaling Pathway / Q000502:physiology*; D060528:Wnt4 Protein / Q000378:metabolism; D051176:beta Catenin / Q000378:metabolism
D011944:Receptors, Androgen; C555581:WNT4 protein, human; D060528:Wnt4 Protein; D051176:beta Catenin; D013739:Testosterone
Androgen; Dihydrotestosterone; Human; Ligand; Skeletal muscle