Causes of Gynecomastia
The causes of gynecomastia are multiple. A search for a common mechanism has not been successful. A number of researchers believe that in many cases (but not all), an altered androgen/estrogen ratio causes changes in cellular elements in breast tissue. This could be due to:
* decrease in production of androgen
* increase in estrogen formation
* decrease in sensitivity of breast tissue to androgens
Certain medications can promote breast growth. They interact with the natural levels of testosterone and estrogen, and upset the balance in some manner. Gynecomastia is a common consequence of estrogen treatment in patients with prostate cancer. Drugs that may cause gynecomastia include:
* Hormones (androgens, anabolic steroids, estrogen agonists)
* Antiandrogens or androgen-synthesis inhibitors
* Antibiotics (isoniazid, ketoconazole, metronidazole)
* Anti-ulcer medications such as cimetidine
* Cancer chemotherapeutics, especially alkylating agents
* Cardiovascular drugs, such as captopril and digitoxin
* Psychoactive agents, such as diazepam and tricyclic antidepressants
* Recreational drugs, such as alcohol and marijuana
* Penicillamine
Alcohol and drugs can cause gynecomastia by mimicking estrogen and stimulating androgen production. Steroids and other excess androgens are sometimes converted by the body into estrogens and consequently cause male breast problems.
To reverse breast growth, it may be possible to change medications.
Men over the age of 50 tend to produce fewer androgens such as testosterone or gain fat tissue that converts androgen into estrogen. In 3 percent of reported cases, gynecomastia can signal lung, liver, or adrenal cancer. Tumors can secrete estrogen, upsetting the hormonal balance.