Androgens are steroid sex hormones produced mainly in the testes that control the development of the male sex organs, the testes, penis, seminal vesicles and prostate gland. They also regulate and maintain secondary male characteristics like the development of body and facial hair, increase in bone and muscle mass and deepening of the voice at puberty. Females also produce small amounts of androgens in the ovaries, but in some cases over production causes androgenisation with characteristics like unwanted body hair.
The main androgens are the male hormone testosterone and its active metabolite dihydrotestosterone (DHT), which is much more potent than testosterone. Both testosterone and DHT bind to the androgen receptor within responsive cells, including brain, bone, hair follicles, testes and prostate cells.
Increased production of or sensitivity to testosterone is thought to be involved in conditions like hypersexuality and aggression in male sex offenders. Also increased sensitivity to DHT and increased conversion of testosterone to DHT is thought to contribute to the hair loss process in male pattern baldness.
The prostate gland
The prostate gland is a small organ that lies just below the bladder and surrounds the top of the urethra, which is the tube that carries urine from the bladder. The prostate gland contributes to the seminal fluid made mainly by the seminal vesicles and the small amount made by the testes, which also contains sperm. Seminal fluid is transported by the urethra through the penis during ejaculation.
Growth and development of the prostate gland is controlled by testosterone, which binds to androgen receptors inside prostate cells. Conditions of the prostate gland include:
- Prostatitis, which is inflammation of the prostate usually due to an infection.
- Benign Prostatic Hyperplasia (BPH), which is an enlarged prostate but is not cancerous.
- Prostate cancer, which is an androgen-dependent tumour and needs testosterone for the cancer cells to grow.
Erectile dysfunction (ED) is also known as impotence in men and is the inability to achieve or maintain a hard erect penis suitable for sexual activity, which is normally the natural response to sexual stimulation. ED is due to decreased blood flow into the penis and can be treated by specific medication taken at the time of planned sexual activity.
Treatments for men’s health problems
Medications available for treating specific men’s health problems include:
- Anti-androgens that block the production of testosterone and its effects on cells containing androgen receptors, and are used to treat prostate cancer; also hypersexuality in male sex offenders.
- Inhibitors of the enzyme 5α-reductase that converts testosterone to DHT, and is used to treat BPH and male pattern baldness.
- Alpha blockers or alpha-adrenergic antagonists that relax muscle cells in the prostate gland and are used to treat symptoms of BPH.
- Inhibitors of the enzyme phosphodiesterase type 5 (PDE5) that widen blood vessels allowing blood flow into penis, and are used to treat ED.
- Prostaglandins that relax smooth muscle and are used to treat ED.
- Dietary supplements containing a naturally occurring 5α-reductase inhibitor, used to support prostate health and to treat BPH and male pattern baldness.