It is well known that testosterone is the hormone that is responsible for the masculine features of men. Testosterone is an androgen, which means it is a male sex hormone. However, this hormone is also found in women albeit in much smaller amounts than in men and it is necessary for normal growth and development. The levels vary by age and gender. A testosterone test may need to be done for various conditions in children, adolescents and adults.
Source of Testosterone
Testosterone is produced at varying levels in different organs within the male and female body. The largest quantity of testosterone is produced by the testicles in males. The pituitary gland by the brain releases luteinizing hormone (LH) to stimulate the testicles to produce testosterone. Significantly smaller quantities of testosterone are produced in the adrenal glands in both men and women. The ovaries also produce small amounts of testosterone in women. This naturally occurring testosterone that is produced within the body is known as endogenous testosterone. Administration of testosterone for whatever reasons is known as exogenous testosterone.
Effects of Testosterone
The effects of testosterone is probably best seen in males. The levels of this hormone are relatively low in young boys. Once they reach puberty then the levels of testosterone rise sharply and peak around the age of 40 years. It gradually declines thereafter. Testosterone has th following effects in the male body:
- Stimulates sperm production by the testicles.
- Promotes the growth of facial and body hair.
- Increases the body muscle bulk.
- Causes the voice to become deeper.
All these effects in males are seen from puberty onwards at the time when testosterone levels rise. Small amounts of testosterone are need in the female body. Testosterone in women has a host of effects that are necessary for health and wellbeing. It plays an important role in brain, bone, vascular and sexual health in women.
Abnormal Levels of Testosterone
High levels of testosterone in females could also have similar effects as high levels in males. However, in women this is considered to be abnormal. It is seen in conditions like polycystic ovarian syndrome (PCOS), ovarian hyperthecosis, adrenal hyperplasia, testosterone-secreting tumors and hyperprolactinemia. The testosterone levels in women rises during pregnancy but this is considered to be normal. Exogenous administration of testosterone in women but this is usually intentional and not pathological (due to a disease).
Similarly low levels of testosterone in males is considered to be abnormal. While a decline in testosterone levels in males naturally occurs with advancing age, it can affect younger men for a host of different reasons. Testicular injury or disease, pituitary gland dysfunction, genetic abnormalities, hemochromatosis, liver cirrhosis, chronic kidney disease, psychological stress, alcoholism and obesity are come of the causes of low testosterone levels in men.
In both men and women this abnormal levels of testosterone (too high in females and too low in males) affects sexual functioning and reproduction. Therefore a testosterone blood test is commonly conducted in men and women who are experiencing sexual dysfunction, including infertility.