In people with type II diabetes, cells are resistant to the effects of the hormone insulin. Now, some diabetes researchers are giving attention to another hormone: the male sex hormone testosterone.
Causes and Symptoms of Diabetes (Type II)
After eating a meal, the level of sugar (specifically glucose) in the blood is relatively high. Insulin, a hormone secreted by the pancreas, enables cells to intake some of this circulating sugar and, consequently, bring blood glucose levels down. Type II diabetes is characterized by a resistance to insulin or decreased insulin production by the pancreas. In these people, blood glucose levels remain high for longer than is normal. Over time, persistently high blood glucose levels can damage the circulatory system, nervous system, kidneys, eyes and heart.
Diabetes symptoms can be subtle at first, and may go unnoticed for years. Some of the signs to look out for are:
- Frequent urination
- Impaired/blurred vision
- Increased frequency of infections or slowed healing of infections
- Unrelenting thirst and hunger.
The most common risk factors for diabetes are obesity, inactivity and a family history of type II diabetes. Age is also a factor, with risk increasing significantly after age 45. Recent evidence suggests that low testosterone levels may be another risk factor in men.
Low Testosterone Levels and Diabetes
Men naturally start to produce less testosterone as they age. Most of the time, this slow decline is due to reduced testosterone synthesis in the testes. In rare cases, low testosterone can be attributed to lowered levels of the hormones produced by the pituitary glands that stimulate testosterone production in the testes.
Interestingly, the level of free testosterone in the blood (i.e. testosterone that is not attached to a protein) is lower in men with type II diabetes than in men with normal insulin sensitivity. Even more interesting is that these men have low testosterone due to decreased pituitary hormones, the far less common cause of low testosterone in aging men.
At this time, researchers don’t know if low testosterone contributes to diabetes, if diabetes impairs pituitary hormone production, or if something else altogether is responsible for both low testosterone and diabetes. However, physicians are becoming aware of the need to test their male diabetic patients for low testosterone, since the two conditions often go hand in hand.
Testosterone Replacement Therapy
Much remains to be learned on the link between testosterone levels and diabetes. If low testosterone does indeed contribute to diabetes, then treatment for diabetes may one day include hormone replacement therapy with testosterone. Effects of testosterone therapy can be negative as well as positive, so the decision to undergo this kind of treatment needs to be considered carefully.
Mayo Foundation for Medical Education and Research. (2008). Testosterone therapy: Can it help older men feel young again? Retrieved January 17, 2010 from the Mayo Clinic Web site: http://www.mayoclinic.com/health/testosterone-therapy/MC00030.
Mayo Foundation for Medical Education and Research. (2009). Type 2 diabetes. Retrieved January 17, 2010 from the Mayo Clinic Web site: http://www.mayoclinic.com/health/type-2-diabetes/DS00585.
Rosen, E. D. (2004). Low testosterone in type 2 diabetes; A hidden epidemic? Retrieved January 17, 2010 from the Diabetes in Control Web site: http://www.diabetesincontrol.com/index.php?option=com_content