INSULIN AND SARCOPENIA IN THE ELDERLY

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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. Muscle mass and strength progressively decline with aging. This process has been termed sarcopenia, and is associated with increased risk of falls and bone fracture, which increase the risk of admission in nursing homes. Further, decreases in muscle mass and strength can lead to a reduction in physical activity, which may have possible effects including weak bone, obesity, and diabetes. Specific Aims and Procedures: 1. To compare the response of muscle (growth and loss) to insulin between healthy seniors and younger controls. This will allow us to test the hypothesis that the response of muscle protein synthesis to insulin is impaired in the healthy seniors. 2. To compare the response of glucose and muscle protein turnover (synthesis and breakdown) to insulin between healthy younger volunteers and younger type 2 diabetic volunteers, and between healthy senior volunteers and senior type 2 diabetic volunteers. In this way we will test the hypothesis that the defect in the response of muscles to insulin is only age-dependent and unrelated to diabetes. Volunteers will be recruited by an IRB-approved advertisement that will be posted at UTMB, local newspapers, and social centers, and by word of mouth. The volunteers will be informed about the risks and the benefits of the studies and will be asked to sign an approved consent form. We hope to learn if the loss of muscle with aging is due to changes in the ability of insulin to grow muscle in senior citizens, and if this is related or not to diabetes.