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The Effect of 5-Alpha Reductase on Testosterone in Men

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Read our disclaimer for details. Identifier: NCT00070733
Recruitment Status : Unknown
Verified October 2003 by Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD).
Recruitment status was:  Recruiting
First Posted : October 10, 2003
Last Update Posted : November 7, 2005
Information provided by:
Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Tracking Information
First Submitted Date  ICMJE October 7, 2003
First Posted Date  ICMJE October 10, 2003
Last Update Posted Date November 7, 2005
Study Start Date  ICMJE August 2003
Primary Completion Date Not Provided
Current Primary Outcome Measures  ICMJE Not Provided
Original Primary Outcome Measures  ICMJE Not Provided
Change History
Current Secondary Outcome Measures  ICMJE Not Provided
Original Secondary Outcome Measures  ICMJE Not Provided
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
Descriptive Information
Brief Title  ICMJE The Effect of 5-Alpha Reductase on Testosterone in Men
Official Title  ICMJE The Role of 5-Alpha Reductase in Mediating Testosterone Actions
Brief Summary The enzyme 5-alpha reductase is present in small amounts in muscle and converts testosterone to dihydrotestosterone (DHT). Testosterone affects lean body tissue, muscle size, muscle strength, and sexual function in men. This study will evaluate how 5-alpha reductase influences the effects of testosterone in young healthy men.
Detailed Description

Testosterone, the predominant circulating androgen in men, serves as the active hormone in some target tissues; however, testosterone effects in other target organs require its conversion to two active metabolites, estradiol 17-beta and DHT. The role of 5-alpha reductase in mediating testosterone's effects on muscle and sexual function remains unclear. This study will determine whether 5-alpha reduction of testosterone to DHT is necessary for mediating effects on fat-free mass, muscle size, muscle strength, and leg power in men. The study will also evaluate the necessity of 5-alpha reductase 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.

Participants in this study will be treated with a drug to suppress endogenous testosterone production. Participants will then be randomly assigned to receive either testosterone and placebo or testosterone and the 5-alpha reductase inhibitor dutasteride. Testosterone will be administered weekly; dutasteride and placebo will both be administered daily. Diet and exercise will be standardized across both groups. Participants will be assessed at study entry and Week 20. Assessments will include measurements such as a DEXA scan, MRI scan, and muscle performance and sexual function tests. Participants will also have blood tests for safety monitoring; blood tests will include measures of hematocrit, liver enzymes (AST and ALT), prostate specific antigen (PSA), and cholesterol.

Study Type  ICMJE Interventional
Study Phase  ICMJE Phase 3
Study Design  ICMJE Allocation: Randomized
Intervention Model: Parallel Assignment
Masking: Double
Primary Purpose: Treatment
Condition  ICMJE Sex Disorders
Intervention  ICMJE
  • Drug: testosterone enanthate
  • Drug: duastride
Study Arms  ICMJE Not Provided
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by Identifier (NCT Number) in Medline.
Recruitment Information
Recruitment Status  ICMJE Unknown status
Enrollment  ICMJE
 (submitted: June¬†23,¬†2005)
Original Enrollment  ICMJE Same as current
Study Completion Date  ICMJE June 2005
Primary Completion Date Not Provided
Eligibility Criteria  ICMJE

Inclusion Criteria

  • General good health and capable of undergoing strength testing
  • Normal testosterone (300-1100 ng/dL), LH, and FSH levels

Exclusion Criteria

  • Currently participating in competitive sports
  • Mental state that would preclude complete understanding of the protocol and compliance
  • Disorder known to cause or be associated with hypogonadism (e.g., pituitary tumors, hyperprolactinemia, HIV infection, or Klinefelter's Syndrome)
  • More than 20% over ideal body weight
  • Disabilities that would prevent participation in strength testing (e.g., amputation of limbs, blindness, severe arthritis, angina, or neurologic disorders such as Parkinson's disease, stroke, or myopathy)
  • Uncontrolled hypertension, diabetes, congestive heart failure, or chronic obstructive lung disease
  • Alcohol or drug dependence in the 6 months prior to study entry
  • Disorders that might be exacerbated by androgen treatment (e.g., benign prostatic hyperplasia or prostate cancer, erythrocytosis [hematocrit > 51% at baseline], or sleep apnea assessed by Berlin's questionnaire)
  • Serum PSA levels > 4 microg/L
  • AST, ALT, or alkaline phosphatase elevation greater than three times the upper limit of normal
  • Creatinine greater than 2 mg/dL
  • Medications that might affect muscle or bone metabolism (e.g., glucocorticoid, rhGH, androgenic steroids, oral androgen precursors such as androstenedione or DHEA) or androgen metabolism, action, or clearance (e.g., dilantin, phenobarbitol, aldactone, flutamide, finasteride)
Sex/Gender  ICMJE
Sexes Eligible for Study: Male
Ages  ICMJE 21 Years to 40 Years   (Adult)
Accepts Healthy Volunteers  ICMJE Yes
Contacts  ICMJE Contact information is only displayed when the study is recruiting subjects
Listed Location Countries  ICMJE United States
Removed Location Countries  
Administrative Information
NCT Number  ICMJE NCT00070733
Other Study ID Numbers  ICMJE R01HD043348-01( U.S. NIH Grant/Contract )
Has Data Monitoring Committee Not Provided
U.S. FDA-regulated Product Not Provided
IPD Sharing Statement  ICMJE Not Provided
Current Responsible Party Not Provided
Original Responsible Party Same as current
Current Study Sponsor  ICMJE Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Original Study Sponsor  ICMJE Same as current
Collaborators  ICMJE Not Provided
Investigators  ICMJE
Principal Investigator: Shalender Bhasin, MD Charles R. Drew University
PRS Account Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Verification Date October 2003

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP