Androgens Play A Crucial Role In The Development Of Androgenetic Alopecia

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Androgen - The Key Player in the Hair Growth Process

Androgens are key players in the hair growth process. And they are closely associated with the condition of Androgenetic Alopecia

Androgen is a generic term with a broad application. It refers to any natural or synthetic compound (usually a steroid hormone) that stimulates or controls the development and maintenance of masculine characteristics in vertebrates. And it does so by binding to Androgen Receptors

Androgens are related to the activity of the accessory male sex organs. And they also play a role in the development of male secondary sex characteristics. In addition, they can be converted to estrogens (the primary female sex hormones) under certain circumstances.
DHT and testosterone
Testosterone (the primary androgen) and DHT (Dihydrotestosterone) are the two most important types of androgens for the development of masculine features and Androgenetic Alopecia DHT is actually a metabolite (bio-chemical modification) of testosterone.
The enzyme 5a-reductase is the main factor promoting DHT's formation. The enzyme forms DHT by reducing the ?4, 5 double-bond in testosterone. This converts testosterone into the much more potent DHT androgen.

Testosterone and DHT are both capable of binding to Androgen Receptors. Though DHT is about 10 time more potent in its activation of androgen receptors than testosterone. The binding of the androgen receptors on cells enables the androgens to stimulate and regulate the development and maintenance of masculine characteristics in vertebrates.

Location and origin of androgens
Prostate glands, testes, hair follicles and adrenal glands are the principal sources of androgen hormones in men. In women the primary sources of androgens are the adrenal glands and ovaries.

The testosterone steroid hormone - which is the principal male sex hormone - is primarily secreted in the testes of males and the ovaries of females. The adrenal glands also secrete a small amount of testosterone. However, in women in particular, other less potent androgens such as dehydroepiandrosterone (DHEA) produced by the adrenal glands can be converted to testosterone by enzymes.
Interaction with androgen receptors
Androgen hormones interact with androgen receptors in their two most potent forms - testosterone and DHT. In some cells, androgen receptors have a direct interaction with the testosterone. While in some other cells, testosterone is first converted into DHT by the enzyme 5-alpha-reductase.

Effects of testosterone
It causes the growth of beard and axillary or body hair.

The effects of testosterone in childhood and puberty -
The following effects are visible among both males and females -
  • Increased oiliness of hair
  • Pubarche (appearance of pubic hair)
  • Axillary hair growth
The effects of testosterone in the late pubertal period -
The following testosterone effects are visible during the late pubertal period among males. They occur in women after prolonged periods of excessive levels of free testosterone.
  • Extension of public hair growth area to thighs and up towards the umbilicus (belly button)
  • Growth of facial hair (sideburns, beard, moustache)
  • Growth of chest hair, periareolar hair, and perianal hair.
Effects of DHT
Facial and body hair growth - DHT significantly contributes to facial and body hair growth among males. Increased levels of DHT among women can result in attributes like hair growth above the lip.

Causing androgenetic alopecia - DHT is supposed to be the primary contributing factor in most cases of androgenetic alopecia.

DHT is supposedly much more potent than testosterone in causing baldness because of its increased affinity for the androgen receptors.

The typical androgen profile of men with androgenetic alopecia
The typical androgen profile of men suffering from androgenetic alopecia are as follows -
  • Lower levels of total testosterone
  • Higher levels of unbound/free testosterone
  • Higher levels of total free androgens including DHT
Sex Hormone Binding Globulin (SHBG) is responsible for binding testosterone and preventing its bioavailability and conversion to DHT. And its presence is typically lower in individuals with high DHT. Sex Hormone Binding Globulin is downregulated by insulin.

Increased levels of Insulin Growth Factor-1 is co-related to vertex balding.

High insulin levels are supposedly the link between metabolic syndromes and baldness.
Effects of increased androgen level among females
An increased androgen level among females results in hirsutism (excessive and increased hair growth). The condition causes excessive and increased hair growth among females in locations that normally have minimal or no terminal hair. Hirsutism may be the symptom of more serious medical problems, especially when it develops well after puberty.

Androgen Insensitivity Syndrome
Androgen Insensitivity Syndrome (AIS) is the condition of human insensitivity to androgens. This condition can result in various problems including ones affecting hair growth.

The hair-growth related problems that AIS carriers often suffer from include reduced axillary and pubic hair.0

Problems arising from various forms of AIS -
  • Complete AIS (CAIS) - Minimal androgenic (pubic or axillary) hair at puberty
  • Partial or incomplete AIS (PAIS) -Thin to normal androgenic hair
  • Reifenstein syndrome - Thin to normal androgenic hair
Anti androgens as preventive measures against androgenetic effects
Anti androgens are any of a group of hormone receptor antagonist compounds that are able to prevent or inhibit the biologic effects of androgens on generally responsive body tissues.

Usually, they counter the androgens by blocking the appropriate receptors. They compete for binding sites on the cells' surfaces, which obstructs the androgens' pathway.