Related Experiment Videos
Testosterone dose-response relationships in healthy young men.
S Bhasin1, L Woodhouse, R Casaburi
1Division of Endocrinology, Metabolism, and Molecular Medicine, Charles R. Drew University of Medicine and Science, Los Angeles, CA 90059, USA. SBHASIN@UCLA.EDU
American Journal of Physiology. Endocrinology and Metabolism
|November 10, 2001
Summary
Testosterone dose impacts muscle mass, strength, and body composition in men. Different bodily processes respond uniquely to testosterone levels, with sexual function and cognition unaffected by dose.
Area of Science:
- Endocrinology
- Exercise Physiology
- Androgen Research
Background:
- Testosterone is known to influence muscle mass and strength.
- The dose-dependent effects and varying requirements for different androgen-dependent processes remain unclear.
Purpose of the Study:
- To investigate the dose-dependent effects of testosterone enanthate on body composition, muscle characteristics, strength, power, sexual and cognitive functions, and various biomarkers.
- To determine if different androgen-dependent processes exhibit similar dose-response relationships.
Main Methods:
- 61 eugonadal men (18-35 years) received GnRH agonist to suppress endogenous testosterone.
- Participants were randomized to weekly injections of 25, 50, 125, 300, or 600 mg testosterone enanthate for 20 weeks.
- Standardized energy and protein intake were maintained.
Main Results:
- Increased fat-free mass, muscle size, strength, and power were dose-dependently correlated with testosterone concentrations.
- Changes in hemoglobin and insulin-like growth factor I (IGF-I) were positively correlated with testosterone.
- Fat mass and high-density lipoprotein (HDL) cholesterol decreased with increasing testosterone dose.
- Sexual function, cognitive function, and prostate-specific antigen (PSA) levels showed no significant changes across doses.
Conclusions:
- Circulating testosterone concentrations are associated with dose- and concentration-dependent changes in body composition, muscle parameters, and metabolic markers.
- A single linear dose-response relationship generally applies, but specific androgen-dependent processes show distinct sensitivities.
- Testosterone dose significantly influences physical and metabolic outcomes, but not sexual function, cognition, or PSA levels in this cohort.