This subproject is one of many research subprojects utilizing the resources provided by a Center grant funded by NIH/NCRR. The subproject and investigator (PI) may have received primary funding from another NIH source, and thus could be represented in other CRISP entries. The institution listed is for the Center, which is not necessarily the institution for the investigator. Elderly persons experience progressive loss of skeletal muscle mass, muscle strength, functional capacity for activities of daily living, have impaired mood, and eventually lose independence. Aging is also associated with a loss of gonadal function and integrity of the growth hormone (GH/IGF-laxis. However, the relationship of deficiencies of these hormones axes to sarcopenia and frailty in aging has not been established or whether there is an interactions of these two hormone systems in maintaining normal muscle mass and function. We hypothesize that both hormone systems regulate musculoskeletal protein mass and contractile fibers by different and complimentary mechanisms and that optimal levels of both testosterone and GH/IGF-1 are necessary to maintain skeletal muscle mass, muscular strength, full functional activities of daily living, quality of life, and independence during the aging process. The findings of this study should result in important mechanistic understanding of the relative contributions of androgen deficiency and hyposomatotropism in elderly persons with frailty related to decreased muscle mass and strength. The results should also provide valuable information for future testing of new, novel treatment strategies which are more tolerable and convenient than parenteral therapies in age associated sarcopenia with frailty.