The Role of 5-alpha Reductase in Mediating Testosterone Actions

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.

Sex

Male

Minimum age

18 Years

Maximum age

50 Years

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 study in the last 3 months?

• DERIVEDTapper J, Arver S, Pencina KM, Martling A, Blomqvist L, Buchli C, Li Z, Gagliano-Juca T, Travison TG, Huang G, Storer TW, Bhasin S, Basaria S. Muscles of the trunk and pelvis are responsive to testosterone administration: data from testosterone dose-response study in young healthy men. Andrology. 2018 Jan;6(1):64-73. doi: 10.1111/andr.12454. PMID 29280355
• DERIVEDBhasin 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 5alpha-reductase inhibitor on fat-free mass in men with suppressed testosterone production: a randomized controlled trial. JAMA. 2012 Mar 7;307(9):931-9. doi: 10.1001/jama.2012.227. PMID 22396515