The Effects of Cyclic Testosterone Administration on Muscle Function in Older Individuals
概览
- 阶段
- 1 期
- 干预措施
- Placebo
- 疾病 / 适应症
- Hypogonadism
- 发起方
- The University of Texas Medical Branch, Galveston
- 入组人数
- 26
- 试验地点
- 1
- 主要终点
- Changes in Basal Muscle Protein Synthesis and Breakdown as Measured by Stable Isotope Metabolic Studies at Baseline and at Five Months
- 状态
- 已完成
- 最后更新
- 13年前
概览
简要总结
The purpose of this study is to determine whether testosterone (male hormone) therapy is effective if administered in a cyclic fashion (periodic dosing) compared to continuous dosing in men aged 60 to 85 years. Effectiveness will be determined based on improvements in body composition, muscle metabolism, muscle strength, and bone metabolism.
详细描述
Men and women undergo a progressive reduction in lean muscle mass (sarcopenia) with advancing age regardless of their level of physical activity. A 12-yr longitudinal study in healthy sedentary older men showed a correlation between loss of muscle cross-sectional area and muscle strength of the thigh, quadriceps, and flexor muscles. Once weakened, older individuals are prone to falls that prevent independent living and diminish the quality of life. There is a need to develop therapies to counteract losses in skeletal muscle strength with aging. Studies show that exercise and testosterone administration increase skeletal muscle mass and strength in older men. However, the increase in muscle strength by testosterone in older men has not been consistent in all studies. Androgens increase muscle mass by either increasing muscle protein synthesis or inhibiting muscle protein breakdown. This proposal will investigate the hypothesis that cyclic testosterone administration (monthly on/off cycles) will preferentially increase muscle protein synthesis and result in a consistent and greater improvement in muscle strength than continuous testosterone administration.
研究者
入排标准
入选标准
- •Availability of transportation (i.e., subjects must be able to provide their own transportation to UTMB).
排除标准
- •Medications such as anticoagulants (Coumadin) and glucocorticoids.
- •History of angina that occurs with exertion or at rest.
- •History of myocardial infarction within the last 12 months.
- •Failure to successfully complete an exercise stress test using the Bruce protocol. Subjects that demonstrate ≥ 0.1 mV horizontal or downsloping ST segment depression, a drop in systolic blood pressure of ≥ 10 mm Hg, and/or frequent or repetitive arrhythmias (defined as ≥ 10 PVC/min, or couplets) during the stress test will be excluded.
- •LDL cholesterol above 200 mg/dL.
- •History of prostatic cancer.
- •Elevated prostate specific antigen (PSA) above 4.0 µg/L, or severe benign prostatic hypertrophy (BPH) by history (frequent urination, reduced stream).
- •Serum total testosterone concentrations of greater than 500 ng/dL.
- •Subjects who engage in high intensity, elite training on a regular basis.
- •Major medical illness such as diabetes, chronic obstructive pulmonary disease, or sleep apnea.
研究组 & 干预措施
Placebo
Weekly placebo treatment for a duration of 5 months.
干预措施: Placebo
Monthly Cycled Testosterone
A month of weekly testosterone treatment alternated by a month of weekly placebo treatment for a duration of 5 months.
干预措施: Testosterone
Monthly Cycled Testosterone
A month of weekly testosterone treatment alternated by a month of weekly placebo treatment for a duration of 5 months.
干预措施: Placebo
Continuous Testosterone
Weekly testosterone treatment for a duration of 5 months
干预措施: Testosterone
结局指标
主要结局
Changes in Basal Muscle Protein Synthesis and Breakdown as Measured by Stable Isotope Metabolic Studies at Baseline and at Five Months
时间窗: 5 Months
The fractional synthetic rate (FSR) of mixed muscle is calculated by directly measuring the incorporation of L-\[ring-13C6\]-phenylalanine into protein (%/hr),, using the precursor-product model: FSR = \[(EP2 - EP1)/(EM•t)\]•60•100, where EP1 and EP2 are the enrichments of bound L-\[ring-13C6\]-phenylalanine in the first and second muscle biopsies, t is the time interval (min) between biopsies, and EM is the mean L-\[ring-13C6\]-phenylalanine enrichment in the muscle intracellular pool.
Changes in Muscle Strength as Measured by Maximal Voluntary Contraction Tests (Arm Curl) at Baseline, One Month, Two Months, Three Months, Four Months, and at Five Months
时间窗: 5 months
Maximum weight (pounds) lifted using Cybex weight machine in a single effort(1-RM) for upper extremities (biceps and triceps) and lower extremities quadriceps and hamstrings).
Changes in Lean Body Mass as Measured by Dual Energy X-ray Absorptiometry (DEXA)
时间窗: 5 months
Lean body mass is expressed in grams as calculated by Hologic DEXA.
次要结局
- Changes in Bone Mineral Density as Measured by Dual Energy X-ray Absorptiometry (DEXA)(5 months)
- Changes in Serum Markers of Bone Turnover.(5 months)
- 9473Changes in Serum Inflammatory Biomarkers and Muscle Inflammatory Cytokines(5 months)