Clinical Trials

The loss of muscle mass and function with age leads to high social and economic costs. Lifestyle interventions that can help maintain muscle mass and function can be beneficial to improve health and decrease the costs associated with loss of independence in the elderly. Muscle proteins accumulate damage during aging, which is suggested to lead to loss of function.  The biological processes that remove damaged proteins and synthesis new proteins appear to be decreased with aging.  Exercise is known to increase the processes that remove older and synthesis newer muscle proteins and may be an effect lifestyle intervention to improve muscle quality and function.  Additionally, specific types of proteins appear to decay with age including contractile and mitochondrial proteins.  Different types of exercise training can increase the making of specific proteins.  The investigators will examine the ability for aerobic and resistance training to increase the quality of mitochondrial and contractile proteins between younger and older people.

There are 3 groups to which you might be assigned.  Assignment to these groups is random (ie. by flip of a coin).

     If you are assigned to…

       -  Group 1 - you will receive no treatments.

       -  Group 2 - you will be given an injection of leuprolide acetate (Lupron) which will temporarily lower sex hormones.  This injection will be given two times during the 7 week treatment period.

       -  Group 3 - you will be given the injections of Lupron but after the second injection, you will also be required to apply a testosterone gel that will result in maintenance of your testosterone levels.  The testosterone gel is rubbed on the upper shoulders, similar to putting on suntan lotion.  You will be shown how to put this on.

     If you are in group 2 or 3 you will be given testosterone gel, a male hormone, at the end of the study to help prevent symptoms such as hot flashes, until your body has time to return to its pre-study hormone levels.  This can take up to 4 weeks.

     In addition to the treatment period, you will also:

       -  If you are in group 1, have 4 fat biopsies that are like a miniature liposuction. The investigators numb the skin before doing the biopsies.  If you are in group 2 or 3, you will also have 1 muscle biopsy at the end of the treatment period.  In addition, if you are in group 2 or 3, you will also have a fat and muscle biopsy before you start the hormone treatment.

       -  All groups will need to spend two days and nights in the Clinical Research Unit of the Mayo Clinic and your meals will be provided by the for 5 days beforehand. You will also need to spend one morning undergoing some initial tests.

       -  You will have your body fat measured before and after the hormone treatment using x-ray like equipment that will expose you to some radiation.

       -  Our measures of fat metabolism use molecules that have a small amount of radioactivity.

     Remuneration is provided.