DHEA+EXERCISE EFFECT ON SARCOPENIA & OSTEOPENIA OF AGING

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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. DHEA declines dramatically with age. Low DHEA levels have been found to correlate with sarcopenia and osteopenia. It is therefore postulated that many physiologic changes of aging are secondary to the decline in DHEA. Thus the objective of the proposed research is to evaluate the effect of DHEA replacement on age-related changes in body composition, muscle function and metabolism, and bone mass in healthy older adults. The specific aims are to evaluate the effects of 10 months of DHEA replacement (50 mg/d) in combination with resistance exercise training on a) total body fat content and lean body mass, intra-abdominal fat volume and thigh muscle area, and muscle protein turnover and synthesis ; b) bone mineral density of the total body, lumbar spine and hip and biochemical markers of bone turnover; and c) insulin sensitivity. Muscle protein synthesis rate will be determined by the incorporation rate of 13C-leucine into skeletal muscle proteins. GC/quadrupole/MS and GC/combustion/MS will be used to quantify 13C-leucine abundance in plasma, muscle free amino acids, and structural muscle proteins. It is hypothesized that DHEA administration will increase muscle and bone mass, decrease visceral fat mass, and increase insulin sensitivity and that these effects will be additive or synergistic with exercise. Healthy but sedentary subjects, aged 65-78 yr. old will be randomized to receive either DHEA, 50 mg/d for ten months. All participants will participate in supervised exercise training programs for four months. The supervised exercise program will consist of resistance training designed to increase muscle mass, strength, and bone mass, and decrease fat mass. The goal of this research is to provide information on the potential role of DHEA replacement therapy in maintaining the physical health and functional capacity of older people.