Production and regulation of testosterone in the human body occurs as a result of the hypothalamus in the brain, the pituitary gland and the testes working together. According to Health Communities, the testes normally produce 4 to 7mg of testosterone each day. Reduced testosterone levels may result if a problem occurs with the hypothalamus, pituitary or testes. These problems may arise due to many factors.
Aging
Health Communities states that testosterone levels in men begin to decline in their 30s, with production decreasing significantly after the age of 50, a condition called andropause. According to the Hormone Foundation, as people become older, glands, such as the pituitary, no longer function as well. Glands in the human body tend to shrink with age and change physical structure. As a consequence, chemicals responsible for regulating testosterone production in the testes become imbalanced, resulting in reduced levels of the hormone.
Genetics
According to the Hormone Foundation, testosterone levels may become affected due to genetic problems. In genetic conditions, such as Prader-Willi syndrome, problems with chromosomes cause problems with hormone production across an individual's life. The most common genetic problem affecting testosterone levels, according to Health Communities, is Klinefelter's syndrome. Other examples include leutenizing hormone-releasing hormone deficiency and Kallmann's syndrome.
Injury and Trauma
Disruption of testosterone levels may occur as result of injury or trauma to one of the body mechanisms responsible for production. If the testes become injured, due to a physical blow or castration, testosterone levels may become significantly affected, states Health Communities. Damage to the testes may also occur, the Hormone Foundation indicates, as a result of radiation and chemotherapy treatments. Sometimes the pituitary gland, hypothalamus or testes may become damaged during surgery, Health Communities says, resulting in disruptions of testosterone. Physical trauma, such as a head injury, may damage the hypothalamus, causing problems in testosterone regulation.
Medical Conditions
A number of medical conditions may affect testosterone levels as well. The Hormone Foundation identifies several of these conditions, including obesity, type 2 diabetes, HIV/AIDS, chronic liver or kidney disease and pituitary tumors. Specifically, Health Communities says that an individual with certain conditions, such as diabetes, hypertension and obesity, poses twice the risk for reduced testosterone. Infection, according to Health Communities, such as meningitis, syphilis or mumps, may also affect testosterone production.
Environmental Factors
Exposure to naturally occurring and man-made chemicals may result in interruption of endocrine system functioning, including the production of testosterone, according to the National Institute of Environmental Health Sciences. These chemicals exist in many places -- in the environments people live in and in the products individuals use every day. The National Institute of Environmental Health Sciences says that some research finds that even low amounts of exposure to these chemicals may disrupt levels of certain hormones, such as testosterone. These chemicals may be found in food, medicines, pesticides and makeup.
References
- Health Communities: Testosterone Deficiency (Hypogonadism) Overview
- Hormone Foundation: Endo 101: Factors That Affect Endocrine Function
- Hormone Foundation: Hormones & You --- Low Testosterone and Men's Health
- National Cancer Institute: Gonads
- National Institute of Environmental Health Sciences: Endocrine Disruptors
