The Role of 5-alpha Reductase in Mediating Testosterone Actions (5aR)
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First Received Date ICMJE | June 28, 2007 | ||||
Last Updated Date | May 12, 2010 | ||||
Start Date ICMJE | November 2002 | ||||
Primary Completion Date | December 2009 (final data collection date for primary outcome measure) | ||||
Current Primary Outcome Measures ICMJE |
Change from baseline in fat-free mass, measured by DEXA scanning [ Time Frame: 20 weeks ] [ Designated as safety issue: No ] | ||||
Original Primary Outcome Measures ICMJE |
Change from baseline in fat-free mass, measured by DEXA scanning | ||||
Change History | Complete list of historical versions of study NCT00493987 on ClinicalTrials.gov Archive Site | ||||
Current Secondary Outcome Measures ICMJE |
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Original Secondary Outcome Measures ICMJE |
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Current Other Outcome Measures ICMJE | |||||
Original Other Outcome Measures ICMJE | |||||
Descriptive Information | |||||
Brief Title ICMJE | The Role of 5-alpha Reductase in Mediating Testosterone Actions | ||||
Official Title ICMJE | The Role of 5-alpha Reductase in Mediating Testosterone Actions | ||||
Brief 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. |
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Detailed Description | Testosterone, the predominant circulating androgen in men, also serves as a prohormone that is converted in the body to two active metabolites, estradiol 17 β and 5-α DHT (DHT). Testosterone serves as the active hormone in some target tissues; however, androgen effects in other target organs require its conversion to estradiol or DHT. The role of 5-α reduction of testosterone in mediating its effects on the muscle and sexual function remains unclear. Therefore, the primary objective of this project is to determine whether 5-α reduction of testosterone to DHT is obligatory for mediating its effects on fat-free mass, muscle size, muscle strength, and leg power in men. The secondary objective is to determine whether 5-α reduction of testosterone is necessary for maintenance of androgen effects on sexual function (sexual desire, overall sexual activity, nocturnal penile tumescence (NPT), response to visual erotic stimulus, and penile rigidity) in men. In order to test these hypotheses about the role of 5-α reduction, we will compare testosterone dose response curves for each outcome measure in the absence and presence of a novel, potent 5-α reductase inhibitor (dutasteride) that inhibits both type 1 and type 2 steroid 5-α -reductase isoenzymes. Healthy young men, 21-40 years of age, will be treated with a long acting GnRH agonist to suppress endogenous testosterone production, and concomitantly, randomly assigned to one of 8 groups: group 1, testosterone enanthate (TE) 50-mg weekly, plus placebo tablets daily; group 2, TE 125-mg weekly plus placebo daily; group 3, TE 300-mg weekly plus placebo daily; group 4, TE 600 mg TE weekly plus placebo; group 5, 50-mg weekly, plus dutasteride 2.5-mg daily; group 6, TE 125-mg weekly, plus dutasteride daily; group 7, TE 300 mg weekly, plus dutasteride daily; group 8, 600-mg TE plus dutasteride daily. Energy and protein intake, and exercise stimulus will be standardized. The following outcomes will be measured at baseline and after 20 weeks: body composition by DEXA scan, deuterium oxide and sodium bromide dilution; thigh muscle volume by MRI scan; muscle performance by measurements of 1-repetition maximum strength and leg power; sexual function by International Index of Erectile Function, Sexual Desire Inventory, and daily logs of sexual activity; and penile erections and rigidity during EEG-coupled, NPT recoding and in response to a visual erotic stimulus; total and free testosterone, DHT, estradiol, SHBG, and LH levels. For safety, we will follow hemoglobin/hematocrit, sleep apnea scores, AST and ALT, PSA, plasma lipids, apolipoproteins, and lipoprotein particles, and prostate examinations. A multi-disciplinary team of investigators, the use of a previously validated "Leydig Cell Clamp" model, the use of a potent inhibitor of both subtypes of 5-alpha reductase enzyme, attention to potential confounding variables such as energy intake and exercise stimulus, and power and effect size should help elucidate the role of 5-alpha reduction in mediating androgen action. This study will enhance our understanding of the biologic role of the steroid 5-alpha-reductase system, and has immediate clinical relevance in establishing whether selective androgen receptor modulators that do not undergo 5-alpha reduction would be useful as anabolic agents. |
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Study Type ICMJE | Interventional | ||||
Study Phase | Phase 4 | ||||
Study Design ICMJE | Allocation: Randomized Endpoint Classification: Safety/Efficacy Study Intervention Model: Parallel Assignment Masking: Double Blind (Subject, Caregiver, Investigator, Outcomes Assessor) Primary Purpose: Treatment |
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Condition ICMJE | Healthy | ||||
Intervention ICMJE |
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Publications * | Bhasin S, Travison TG, Storer TW, Lakshman K, Kaushik M, Mazer NA, Ngyuen AH, Davda MN, Jara H, Aakil A, Anderson S, Knapp PE, Hanka S, Mohammed N, Daou P, Miciek R, Ulloor J, Zhang A, Brooks B, Orwoll K, Hede-Brierley L, Eder R, Elmi A, Bhasin G, Collins L, Singh R, Basaria S. Effect of testosterone supplementation with and without a dual 5α-reductase inhibitor on fat-free mass in men with suppressed testosterone production: a randomized controlled trial. JAMA. 2012 Mar 7;307(9):931-9. | ||||
* Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline. |
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Recruitment Information | |||||
Recruitment Status ICMJE | Completed | ||||
Estimated Enrollment ICMJE | 184 | ||||
Completion Date | March 2010 | ||||
Primary Completion Date | December 2009 (final data collection date for primary outcome measure) | ||||
Eligibility Criteria ICMJE | Inclusion Criteria:
Exclusion Criteria:
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Gender | Male | ||||
Ages | 18 Years to 50 Years | ||||
Accepts Healthy Volunteers | Yes | ||||
Contacts ICMJE | Contact information is only displayed when the study is recruiting subjects | ||||
Location Countries ICMJE | United States | ||||
Administrative Information | |||||
NCT Number ICMJE | NCT00493987 | ||||
Other Study ID Numbers ICMJE | R01HD043348, R01HD043348 | ||||
Has Data Monitoring Committee | |||||
Responsible Party | Dr. Shalender Bhasin, Boston University Medical Center | ||||
Study Sponsor ICMJE | Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | ||||
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Investigators ICMJE |
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Information Provided By | Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD) | ||||
Verification Date | January 2009 | ||||
ICMJE Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP |