Testosterone is the male hormone
concerned with the development of male reproductive tissues e.g. prostate and
testis. It is also associated with promoting secondary sexual characters and
increasing muscle and bone mass and promoting growth of the body.
Deficiency of testosterone is also termed as hypogonadism or androgen deficiency syndrome. In the United States, about 4 million men are affected by low levels of testosterone. Usage of testosterone replacement therapy (TRT) in the elderly men is quite common.
Secretion of testosterone in a normal male is controlled by two parts of the brain - the hypothalamus and the pituitary. The hypothalamus in the brain releases GnRH, which in turn stimulates the release of follicle-stimulating hormone (FSH) and luteinizing hormone (LH) from the anterior pituitary. Luteinizing hormone triggers the production of testosterone from the testes.
There are types of hypogonadism- primary hypogonadism is the commonest type; others are secondary hypogonadism and mixed hypogonadism, which is the rarest type.
Primary hypogonadism is seen when the testes fail to respond to FSH and LH. . Secondary hypogonadism is seen when FSH and LH are produced in insufficient quantities.
Mixed hypogonadism is seen when there are some defects in the testes, and hypothalamus or pituitary.
Signs and symptoms of testosterone deficiency:
The diagnosis of testosterone deficiency requires the assessment of testosterone level in the serum. The average lower level of normal of testosterone in young men is 300ng/dL and symptoms of deficiency appear below this threshold. Testosterone deficiency results in -
• Improper and incomplete sexual development
• Reduced libido or sexual activity
• Gynecomastia or development of breast in men
• Small testes
• Loss of body hair especially from the armpits and pubis
• Hot flashes and sweats
• Decreased sperm count
• Mild-to-moderate anemia
• Sleep disturbances
• Increased body fat
• Lack of concentration
• Loss of memory
A circadian rhythm is depicted by the serum testosterone level with high values in the morning. The testosterone values are therefore tested in the morning blood samples.
Testosterone replacement therapy (TRT) is beneficial in treating deficiency of testosterone. It can bring positive results in improving erectile dysfunction, libido, cognition and mood, body strength and composition, and bone density. Benefits of testosterone replacement therapy are listed below:
Testosterone replacement therapy has a positive impact on the sexual thought, successful intercourse, achievement of erections and motivation. TRT improves the overall sexual performance in testosterone-deficient males.
Mood and Cognition:
Mixed results are attained with testosterone replacement therapy with respect to mood and cognition.
Body Composition and Strength:
Testosterone replacement therapy remarkably alters the body mass without bringing any change in the overall weight of the body.
Bone Mass Density (BMD)
In hypogonadism, testosterone replacement therapy increases the bone mass density. Testosterone plays an important role in promoting bone formation and prevents bone breakdown.
Possible side effects of testosterone replacement therapy (TRT) may vary from mild to serious and even lethal. Acne eruption, gynecomastia, male pattern baldness and suppression of spermatogenesis are the mild adverse effects while worsening sleep apnea, benign prostatic hyperplasia (BPH), worsening of breast cancer, prostate cancer and cardiovascular ailments are the serious effects associated with testosterone replacement therapy.
Testosterone replacement therapy (TRT) aims at restoring serum testosterone within the normal range. Men receiving testosterone replacement therapy should be regularly monitored and baseline testosterone concentrations should be recorded at 3 to 6 months after the onset of the therapy.
Before starting the treatment, digital rectal examination and prostate-specific antigen (PSA) testing should be done to rule out prostate enlargement or cancer. Regular check up for hematocrit should also be done to check the incidence of polycythemia.
TRT can cause lipid and liver abnormalities so lipid profile and liver function test should be done periodically during the therapy.
Testosterone products are available in various forms such as oral, parenteral (not oral), transdermal (absorbed through skin), pellets (inserted just below the skin) and buccal.
No optimal delivery method for testosterone has been established.
Commonly available testosterone gels are Testim, Androgel and Fortesta. Axiron is available as a solution of testosterone.
Esterified testosterone is used as intramuscular injections.
Finally, it can be said that testosterone replacement therapy is beneficial in treating the deficiency of testosterone. Proper counseling and medication therapy management are crucial for adequate administration of TRT.