In a nutshell
This paper described the symptoms and treatment of male hypogonadism.
In males, the testes function to produce testosterone and sperm. Testosterone is crucial for the development of male sexual characteristics and spermatogenesis (production of sperm). Spermatogenesis is critical for male fertility. Male hypogonadism is caused by a failure to produce normal amounts of sperm or testosterone. This occurs when regulation of testosterone is impaired.
Primary hypogonadism occurs when the testes are affected. Testosterone levels are decreased, sperm production is affected and there is increase of gonadotropins (hormone crucial for fertility). Fertility cannot be restored by hormonal therapy. Patients would have to consider using donor sperm or assisted reproductive technologies to have children. Secondary hypogonadism occurs when there is low testosterone concentration, reduced sperm production and gonadotropins. Fertility can be restored with gonadotropin releasing hormone (GnRH; a protein important in fertility) and gonadotropin therapy.
Methods & findings
Causes of primary hypogonadism include genetic mutations, mumps-related orchitis (swelling of the testes resulting from the virus that causes mumps) and trauma. Chemotherapy, radiation and medications can also cause primary hypogonadism. Causes of secondary hypogonadism include GnRH deficiency, excess prolactin (hormone; most important in causing females to produce milk) and pituitary gland (the part of the body that controls all hormones) damage. Critical illness, starvation and medications can also cause secondary hypogonadism.
The diagnosis of male hypogonadism is based on assessment of signs and symptoms as well as low testosterone levels. Symptoms include: decrease of libido (sexual drive), spontaneous erection and increased testicular volume. Breast growth and decreased bone and muscle mass could also be present.
For men with confirmed diagnosis of hypogonadism, testosterone-replacement therapy is used. Men with prostate or breast cancers should not take testosterone therapy. Testosterone can be administered through injections, transdermally (across the skin) or orally with pills and tablets.
One study showed that testosterone-replacement therapy improved sexual function. Trials have shown that testosterone-replacement therapy is associated with increased bone density and decreased fat mass. Erythrocytosis (increase in proportion of red blood cells) is an adverse effect of testosterone-replacement therapy. Additionally, testosterone not from the body can act as a contraceptive by inhibiting sperm production.
The bottom line
The authors concluded that long term effects and risks of testosterone have not been fully studied, and large controlled trials are needed.