Testosterone is a steroid hormone from the androgen group. In mammals, testosterone is primarily secreted in the testes of males and the ovaries of females, although small amounts are also secreted by the adrenal glands. It is the principal male sex hormone and an anabolic steroid. Testosterone is evolutionarily conserved through most vertebrates, although fish make a slightly different form called 11-ketotestosterone.
In men, testosterone plays a key role in health and well-being as well as preventing osteoporosis. On average, an adult human male body produces about forty to sixty times more testosterone than an adult human female body, but females are, from a behavioral perspective (rather than from an anatomical or biological perspective), more sensitive to the hormone. However, the overall ranges for male and female are very wide, such that the ranges actually overlap at the low end and high end respectively.
Adult testosterone effects are more clearly demonstrable in males than in females, but are likely important to both sexes. Some of these effects may decline as testosterone levels decrease in the later decades of adult life.
* Libido and clitoral engorgement/penile erection frequency
* Regulates acute HPA response under dominance challenge
* Mental and physical energy
* Maintenance of muscle trophism
* The most recent and reliable studies have shown that testosterone does not cause or produce deleterious effects on prostate cancer. In people who have undergone testosterone deprivation therapy, testosterone increases beyond the castrate level have been shown to increase the rate of spread of an existing prostate cancer.
* Recent studies have shown conflicting results concerning the importance of testosterone in maintaining cardiovascular health. Nevertheless, maintaining normal testosterone levels in elderly men has been shown to improve many parameters which are thought to reduce cardiovascular disease, risk such as increased lean body mass, decreased visceral fat mass, decreased total cholesterol, and glycemic control.
* Under dominance challenge, may play a role in the regulation of the fight-or-flight response