The Effect of 5-Alpha Reductase on Testosterone in Men - Full Text View

Sponsored by:	Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
Information provided by:	Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
ClinicalTrials.gov Identifier:	NCT00070733

Purpose

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.

Condition	Intervention	Phase
Sex Disorders	Drug: testosterone enanthate Drug: duastride	Phase III

Drug Information available for: Testosterone Methyltestosterone Oxymesterone Testosterone enanthate Testosterone Propionate Testosterone undecanoate

U.S. FDA Resources

Study Type:	Interventional
Study Design:	Treatment, Randomized, Double-Blind, Placebo Control, Parallel Assignment, Safety/Efficacy Study
Official Title:	The Role of 5-Alpha Reductase in Mediating Testosterone Actions

Further study details as provided by Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD):

Estimated Enrollment:	184
Study Start Date:	August 2003
Estimated Study Completion Date:	June 2005

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.

Eligibility

Ages Eligible for Study:	21 Years to 40 Years
Genders Eligible for Study:	Male
Accepts Healthy Volunteers:	Yes

Criteria

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)

Contacts and Locations

Please refer to this study by its ClinicalTrials.gov identifier: NCT00070733

Locations

United States, California
Charles R. Drew University	Recruiting
Los Angeles, California, United States, 90059
Contact: Shalender Bhasin, MD 323-563-9353

Sponsors and Collaborators

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

Investigators

Principal Investigator:

Shalender Bhasin, MD

Charles R. Drew University

More Information

Study ID Numbers:	R01 HD43348-01
Study First Received:	October 7, 2003
Last Updated:	November 4, 2005
ClinicalTrials.gov Identifier:	NCT00070733
Health Authority:	United States: Federal Government

Keywords provided by Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD):

Testosterone
5-alpha Reductase
Muscle Strength
Libido

Sexual Function
Muscle Mass
Testosterone 5-alpha-Reductase

Study placed in the following topic categories:

Genital Diseases, Female
Testosterone
Sexual Dysfunction, Physiological

Methyltestosterone
Genital Diseases, Male
Testosterone 17 beta-cypionate

Additional relevant MeSH terms:

Anabolic Agents
Antineoplastic Agents, Hormonal
Antineoplastic Agents
Therapeutic Uses
Physiological Effects of Drugs

Hormones, Hormone Substitutes, and Hormone Antagonists
Hormones
Pharmacologic Actions
Androgens

ClinicalTrials.gov processed this record on January 16, 2009