The Effect of Mixed Exercise and Metabolic Stress Upon Pituitary Secretion in Relationship to Age in Healthy Men: a Pilot Study
Trial Snapshot
- Phase
- Phase 1
- Status
- Completed
- Sponsor
- Mayo Clinic
- Enrollment
- 40
- Locations
- 1
- Primary Endpoint
- Change in Testosterone concentration after 30 minutes of exercise
Study Overview
Brief Summary
Aging in men reduces the amount of luteinizing hormone (LH) and testosterone (Te) secreted in each burst. Stress-associated mechanisms introduced by acute illness and chronic disease decrease LH and Te secretion further. A major unresolved issue is whether the aging process heightens the negative effects of a stressor (whether physical or metabolic) upon LH and Te secretion. This study will assess LH and Te secretion in response to a physical stressor (maximal exercise) and a common metabolic stressor (hyperglycemia) as a function of age in healthy men ages 18-80 yr.
Study Design
- Study Type
- Interventional
- Allocation
- Randomized
- Intervention Model
- Crossover
- Primary Purpose
- Basic Science
- Masking
- Double (Participant, Investigator)
Eligibility Criteria
- Ages
- 18 Years to 80 Years (Adult, Older Adult)
- Sex
- Male
- Accepts Healthy Volunteers
- Yes
Inclusion Criteria
- •Community dwelling, healthy men age 18 to 80
- •Body-Mass Index (BMI) 18-30 kg/m2
- •Willingness to provide written informed consent
- •Physician acceptable screening ECG for participants 60 years and older
Exclusion Criteria
- •recent use of psychotropic or neuroactive drugs (within five biological half-live)
- •obesity (outside weight range above)
- •acute weight change (loss or gain of >2 kg in 6 weeks
- •Laboratory test results not deemed physician acceptable
- •triglycerides > 300
- •creatinine > 1.5 mg/dL
- •liver functions tests twice upper limit of normal
- •electrolyte abnormality
- •anemia; hemoglobin < 12.0 gm/dL
- •drug or alcohol abuse
- •psychosis, depression, mania or severe anxiety
- •acute or chronic organ-system disease
- •endocrinopathy, other than primary thyroidal failure receiving replacement
- •untreated osteoporosis
- •nightshift work or recent transmeridian travel (exceeding 3 time zones within 7 days of admission)
- •PSA > 4.0 ng/mL, History or suspicion of prostatic disease (elevated PSA,indeterminate nodule or mass, obstructive uropathy)
- •History of carcinoma (excluding localized basal cell carcinoma removed or surgically treated with no recurrence
- •History of thrombotic arterial disease (stroke, TIA, MI, angina) or deep vein thrombophlebitis
- •History of CHF, cardiac arrhythmias, congential QT prolongation, and medications used to treat cardiac arrhythmias
- •Gynecomastia > 2 cm, untreated
- •Untreated gallbladder disease
- •History of smoking greater than one ppd.
Arms & Interventions
Hyperglycemia
Hyperglycemia (rest controlled) will be induced by i.v. injection of 25 mL of dextrose 50% over 3 minutes with the subject supine. Includes blood draws and fasting requirements.
Intervention: Blood Draws (Procedure)
Saline
Saline (rest controlled) will be induced by i.v. injection of 25 mL of saline over 3 minutes with the subject supine. Includes blood draws and fasting requirements.
Intervention: Fasting procedure (Other)
Saline
Saline (rest controlled) will be induced by i.v. injection of 25 mL of saline over 3 minutes with the subject supine. Includes blood draws and fasting requirements.
Intervention: Blood Draws (Procedure)
Hyperglycemia
Hyperglycemia (rest controlled) will be induced by i.v. injection of 25 mL of dextrose 50% over 3 minutes with the subject supine. Includes blood draws and fasting requirements.
Intervention: Fasting procedure (Other)
Saline
Saline (rest controlled) will be induced by i.v. injection of 25 mL of saline over 3 minutes with the subject supine. Includes blood draws and fasting requirements.
Intervention: Saline (Drug)
Hyperglycemia
Hyperglycemia (rest controlled) will be induced by i.v. injection of 25 mL of dextrose 50% over 3 minutes with the subject supine. Includes blood draws and fasting requirements.
Intervention: Hyperglycemia (Drug)
Exercise
Monitored exercise of 7-minute biking, 2-minute arm weights and a blood draw at the 10-minute time point will be repeated 3 times,which takes 30 minutes.
Bilateral arm curls begin at 20 pounds and decrease by 5 pounds as needed to sustain 2 minutes of exercise at a rate of 1 complete curl every 2 seconds.
Includes blood draws and fasting requirements.
Intervention: Exercise (Other)
Exercise
Monitored exercise of 7-minute biking, 2-minute arm weights and a blood draw at the 10-minute time point will be repeated 3 times,which takes 30 minutes.
Bilateral arm curls begin at 20 pounds and decrease by 5 pounds as needed to sustain 2 minutes of exercise at a rate of 1 complete curl every 2 seconds.
Includes blood draws and fasting requirements.
Intervention: Blood Draws (Procedure)
Exercise
Monitored exercise of 7-minute biking, 2-minute arm weights and a blood draw at the 10-minute time point will be repeated 3 times,which takes 30 minutes.
Bilateral arm curls begin at 20 pounds and decrease by 5 pounds as needed to sustain 2 minutes of exercise at a rate of 1 complete curl every 2 seconds.
Includes blood draws and fasting requirements.
Intervention: Fasting procedure (Other)
Outcomes
Primary Outcomes
Change in Testosterone concentration after 30 minutes of exercise
Time Frame: 30 minutes after initiating exercise
During the exercise visit subjects will perform an exercise test on a bike and lift weights with both arms for a total of 30 minutes.
Secondary Outcomes
No secondary outcomes reported
Investigators
Johannes D. Veldhuis
PI
Mayo Clinic