Maintenance of muscle mass in adult male mice is independent of testosterone

Testosterone is considered a potent anabolic agent in skeletal muscle with well-established role adolescent growth and development males. However, the of testosterone regulation mass function throughout lifespan has yet to be fully established. While some studies suggest that important for maintenance mass, an understanding this hormone plays young, adult, old males normal low serum levels lacking. We investigated by examining effect orchiectomy-induced depletion C57Bl6 male mice at ages ranging from early postnatal through age (1.5-, 5-, 12-, 24-month mice). Following 28 days depletion, we assessed fiber cross-sectional-area (CSA) tibialis anterior, gastrocnemius, quadriceps muscles. In addition, measured global rates protein synthesis degradation using SuNSET method, western blots, enzyme activity assays. Twenty-eight resulted reduced two youngest cohorts, but had no oldest cohorts. Mean CSA decreased only cohort anterior muscle. general increase proteasome all ages. No change was detected terminal time point. These data within physiological concentrations, may not critical mature mice; however, young crucial growth.