Effects of resistance exercise load on androgen receptor–DNA binding, androgen regulated gene expression, and β-catenin mediation in human skeletal muscle.

The purpose of the study was to determine the effect low (LL) and high (HL) load resistance exercise on serum total and free testosterone, and muscle testosterone, dihydrotestosterone (DHT), androgen receptor (AR), and AR-DNA binding, β-catenin, and AR-regulated/responsive gene expression. Ten participants completed LL and HL resistance exercise with samples collected pre-, 3h post-, and 24h post-exercise. Separate 2x3 factorial repeated measures ANOVAs were completed. Serum free and total testosterone significantly decreased 3h post-exercise with free testosterone remaining significantly decreased 24h post-exercise in both conditions (p<.05). No significant differences were observed in muscle AR, testosterone, or DHT in either condition (p >.05). In response to HL, AR-DNA binding significantly increased at 3h post-exercise (p<.05), whereas no significant differences were observed in response to LL (p>.05). Muscle β-catenin content was significantly greater in HL condition (p<.05). No significant/practical differences were observed in AR, MyoD, MYOG, IGF-1Ea, or p21-cip1 expression (p>.05).