Testosterone is an androgen, which is a male hormone. Accordingly, they are most prevalent in males following the onset of puberty, although it does exist in all women. Testosterone regulates many bodily functions, though most of them are sexual in nature and gender-specific. In addition to natural occurrence in the body, testosterone appears in pharmaceuticals and is the primary ingredient of anabolic steroids.
Cardiovascular Disease
In "Testosterone: Action, Deficiency, Substitution," authors E. Nieschlag and H.M. Behre suggest that testosterone plays a role in cardiovascular disease. They state that 16 out of 32 cross-sectional analyses identified that patients with coronary artery disease had lower levels of testosterone than otherwise healthy patients. Moreover, no studies identified patients with such cardiovascular disease that had high testosterone levels. Alternately, studies did show a positive correlation between testosterone and myocardial mass. Accordingly, the authors concluded that testosterone has at least a neutral effect, if not a positive effect, on patients with cardiovascular diseases.
Androgenic Effects
According to Charles Yesalis in "Anabolic Steroids in Sport and Exercise," testosterone has androgenic effects in both men and women. In men, testosterone increases the length and girth of the penis during puberty, develops and enlarges the prostate, stimulates hair growth everywhere but the crown of the head, causes hair loss from the scalp and increases sexual virility. In women, androgenic effects include an increase in length and girth of the clitoris, the development of either anovulation or polycystic ovaries, hair growth everywhere but the crown of the hair, hair loss on the scalp and an increase in virility.
Anabolic Effects
Yesalis states that testosterone has anabolic implications in males as well as females. In men, testosterone will increase muscle mass as well as strength, decrease lipids, enlarge the larynx and vocal cords, stimulate long bone growth and increase the mass of RBCs. In women, testosterone has the same exact anabolic effects as it does in men. Unfortunately, the anabolic effects of testosterone are sex-specific, rendering these effects relatively negative in women unless intentional.
Behavior
In "Biological Psychology," James Kalat suggests that testosterone influences behavior. Within 15 minutes of testosterone release, sexual behavior will change. Physiological effects, such as the engorgement of genitalia, help facilitate these behavioral alterations. Kalat states that evidence exists that testosterone renders both men and women more aggressive and energetic. Alternately, Kalat asserts that these effects are indirect, in that testosterone actually changes the way the brain processes stimuli rather than altering sensations themselves. Furthermore, behavior can induce testosterone release, as is in the case with manual sexual stimulation or during courtship. Alternately, Kalat explains that modifying testosterone levels will not alter sexual behaviors, but rather change the course of arousal. In other words, in the case of sex offenders, while testosterone reduction will not reduce the inclination to commit sex crimes, it will reduce instances of sexual arousal. Kalat mentions that studies show that drugs that reduce testosterone can control child molesters, but that same study indicated a high attrition of participants.
References
- "Testosterone: Action, Deficiency, Substitution"; E. Nieschlag, Hermann M. Behre, and Susan Nieschlag; 2004
- "Anabolic Steroids in Sport and Exercise"; Charles Yesalis; 2000
- "Biological Psychology"; James W. Kalat; 2009
