CompletedPhase 4

The Role of 5-alpha Reductase in Mediating Testosterone Actions

United States184 participantsStarted 2002-11

Plain-language summary

In normal men, the male hormone testosterone affects a number of things in the body including muscle function and sexual function. An enzyme in the body called 5-alpha reductase converts testosterone into another form called dihydrotestosterone (DHT) which has slightly different effects. The purpose of this study is to find out how different amounts of the two different forms of testosterone affect muscle function and sexual function in healthy young men like you. This will be done by giving the men participating in the study different combinations of hormone-related medication for 20 weeks and making measurements before, during and after the medications to look for changes in lean body tissue, muscle size, muscle strength and leg power, as well as sexual function and sexual activity in all participants.

Who can participate

Age range

18 Years – 50 Years

Sex

MALE

See this in plain English?

AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.

Inclusion Criteria: * Healthy males between 18 and 50 years of age. * Ambulatory, physically active, but not in competitive sports. * Eugonadal: Normal Serum Testosterone (300-1100 nmol/L). * Normal LH * Normal FSH * Able and willing to comply with the trial protocol. Exclusion Criteria: * Known to have a primary or secondary hypogonadism? (e.g. pituitary disease, HIV infection, Klinefelter's Syndrome) * BMI \> 35 * Disability that precludes participation in exercise testing * Alcohol or illicit drug use in the preceding 6 months that would interfere with participation and compliance with the protocol * Known disorder that would be exacerbated by androgen treatment e.g. benign prostate hyperplasia, prostate Ca, erythrocytosis, sleep apnea) * Any abnormalities in the following laboratory tests PSA \> 4 ng/ml AST, ALT or Alkaline Phosphatase \> 3x ULN? Creatinine level \> 2 mg/dL Hematocrit \> 51% * Osteoporosis by DEXA BMD T-Score \< -2.5 * Use of medications that affect muscle or bone metabolism within the previous 3 months ?(e.g. glucocorticoids, growth hormone, androgenic steroids, oral androgen precursors -i.e. androstenedione or DHEA) * Use of medications that affect androgen metabolism, action or clearance within the previous 3 months? (e.g. dilantin, phenobarbital, aldactone, flutamide, finasteride and Ketoconazole) * Use of ketoconazole or other potent CYP3A4 inhibitors that may affect clearance of dutasteride * Use investigational medication as part of a research s…

Questions worth asking your doctor

Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.

1Based on my diagnosis and history, is this trial worth exploring for me — or is there a standard treatment we should try first?
2What does this trial's phase tell us about how much is already known about its safety and benefit?
3What would taking part actually involve for me — visits, tests, time, and travel?
4What are the known and possible risks or side effects I should weigh, and how would they be monitored?
5If this trial isn't the right fit, what other options or trials would you suggest I look into?

Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.

Questions for the trial coordinator

The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.

1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?

A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.

What they're measuring

Change from baseline in fat-free mass, measured by DEXA scanning

Timeframe: 20 weeks

Trial details

NCT IDNCT00493987

SponsorEunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Sponsor typeNIH

Study typeINTERVENTIONAL

Primary completion2009-12

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