Aging
Conditions
Keywords
Growth hormone secretagogue, Body composition, Functional ability, Aging, Sarcopenia
Brief summary
The purpose of this study is to determine whether treatment of healthy older men and women with oral MK-677 for 12 months will enhance pulsatile GH release and increase mean GH and IGF-I concentrations into the range of young adults and will have favorable effects on body composition and functional ability on older adults.
Detailed description
This is a two year, double-blind, placebo-controlled cross-over trial of once daily administration of MK-677, an oral GH secretagogue, to healthy older adults. During the first year, subjects will be randomized to MK-677 or placebo treatment. In each of three subgroups of subjects (men, women off and women on hormone replacement therapy), 16 subjects will receive MK-677 and 8 will receive placebo. After 1 year, the subjects who received placebo will be switched to MK-677 treatment; the subjects who received MK-677 for the first year will be randomized to either placebo or MK-677 for the second year of the study.The study will test changes in GH, IGF-I, body composition and function.
Interventions
Sponsors
Study design
Eligibility
Inclusion criteria
* Healthy men and women 60 years of age, with a body mass index of \< 35 kg/m2.
Exclusion criteria
* Medication known to affect GH secretion, other than estrogen replacement therapy * Coronary artery disease, * Congestive heart failure, * Peripheral vascular disease, * Diabetes mellitus (requiring insulin or an oral hypoglycemic agent), * Significant hypertension (BP \>180 systolic or \>100 diastolic at rest); * Renal, hepatic, pulmonary disease; * Untreated hypothyroidism, untreated hyperthyroidism; * History of seizure disorder; * History of malignancy (other than some skin cancers), history of active chronic infections (e.g., HIV, tuberculosis). * Hematocrit \< 40%, men, \< 36%, women * History of daily tobacco use within past 3 months * Chronic alcohol abuse * Strenuous exercise for average of more than 60 min/day * Investigational drug within past 6 weeks * Psychiatric history, especially anorexia nervosa * Transmeridian travel within 2 weeks prior to or during study
Design outcomes
Primary
| Measure | Time frame |
|---|---|
| Safety determined by routine laboratory tests at 1 to 3 month intervals, yearly pap smears and mammograms | — |
| At 12 months: 24-hour mean growth hormone concentrations | — |
| Insulin-like growth factor-I concentrations | — |
| Body weight and fat mass, specifically abdominal visceral fat | — |
| Fat-free mass | — |
Secondary
| Measure | Time frame |
|---|---|
| Insulin sensitivity | — |
| Lipid profile | — |
| Resting metabolic rate | — |
| Aerobic exercise capacity | — |
| at 12 months: Growth hormone secretory dynamics | — |
| effects of gender and HRT on primary outcomes | — |
| effects of treatment in year 2: Year 2 outcomes include effects of continuation on MK-677, or crossover to placebo, placebo to MK-677 | — |
| bone mineral density at end of year 2. | — |
| Exploratory outcomes: | — |
| Isokinetic muscle strength (knee and shoulder) | — |
| Thigh muscle cross-sectional area | — |
| Function tests (timed walks, stair climb, chair rise) | — |
| Quality of life assessments | — |
Countries
United States