androgenic alopecia

Examples of androgenic alopecia in the following topics:

• Hair and Hormones

  • Androgenic alopecia also occurs in chimpanzee and orangutans.
  • Much research concerns the genetic basis of androgenic alopecia.
  • Since androgens and their interaction with the androgen receptor are the cause of AGA, the androgen receptor gene plays an important part in its development.
  • Androgenic alopecia is polygenetic and appears to have a strong interaction with age as shown by the fact that visible hair loss at a distance is apparent in approximately 80% of males by age 80.
  • Men with androgenic alopecia typically have higher levels of 5-alpha-reductase, lower levels of total testosterone, higher levels of unbound/free testosterone, and higher levels of total free androgens including DHT. 5-alpha-reductase is responsible for converting free testosterone into DHT.

• Alopecia

  • Alopecia areata (AA) is a medical condition in which hair is lost from some or all areas of the body.
  • Alopecia usually affects the hair of the scalp, but can also cause the loss of hair from the eyebrows, eyelashes, and body.
  • Exclamation point hairs are often present in alopecia.
  • In terms of adapting to the disease rather than treating in an effort to cure, wigs are often used by those with alopecia, particularly alopecia totalis, in which hair is entirely lost from the scalp.
  • Photographs of men displaying the classic spot baldness of alopecia areata.

• Adrenal Cortex

  • The adrenal cortex is devoted to the synthesis of corticosteroid and androgen hormones.
  • The most important androgens include:
  • Dihydrotestosterone (DHT): a metabolite of testosterone, and a more potent androgen than testosterone in that it binds more strongly to androgen receptors.
  • Androstenedione (Andro): an androgenic steroid produced by the testes, adrenal cortex, and ovaries.
  • While androstenediones are converted metabolically to testosterone and other androgens, they are also the parent structure of estrone.

• Target Cell Specificity

  • An XY fetus will develop along a female pathway if the target cells fail to respond to androgen.
  • This androgen insensitivity occurs when the receptors on the target cells are unable to accept the hormone due to an impairment in receptor shape.
  • In some instances, alterations of receptor structure due to a genetic mutation can lead to a reduction in hormone–receptor affinity, as in the case of androgen insensitivity.

• Overview of the Adrenal Glands

  • The cortex mainly produces mineralcorticoids, glucocorticoids, and androgens, while the medulla chiefly produces adrenaline and nor-adrenaline.

• Chemotherapy and Hair Loss

  • Therefore, alopecia, or, hair loss, is a common, unwanted effect of chemotherapy.

• Pineal Gland and Gonads

  • The testes produce androgens, which allow for the development of secondary sex characteristics and the production of sperm cells.
  • Testosterone, the most prominent androgen in males, stimulates the development and functioning of the primary sex organs .
  • The testes produce androgens, such as testosterone, which regulate primary sex organ development and function, as well as the development of secondary sex characteristics and the production of sperm cells.
  • Male testes produce androgens, while female ovaries produce estrogen and progesterone.

• Adrenal Medulla

  • The adrenal cortex is devoted to the synthesis of corticosteroid and androgen hormones.

• Congenital Adrenal Hyperplasia

  • CAH is a genetic disorder in which girls are masculinized because the adrenal glands secrete large amounts of androgen during prenatal development.
  • The extra androgen does not affect a baby boy's physical development, but in baby girls it can enlarge the clitoris so that it resembles a penis.
  • During childhood and adolescence, girls with CAH prefer masculine activities and male playmates to a much greater extent than girls not exposed to these amounts of androgen.
  • Synthesis of cortisol shares steps with synthesis of mineralocorticoids such as aldosterone, androgens such as testosterone, and estrogens such as estradiol.
  • supplying enough glucocorticoid to reduce hyperplasia and overproduction of androgens or mineralocorticoids

• Anabolic Steroids and Muscles

  • Anabolic steroids , known technically as anabolic-androgen steroids (AAS) or colloquially as "steroids" (or even "roids"), are drugs that mimic the effects of testosterone and dihydrotestosterone in the body.
  • Anabolic steroids also have androgenic and masculinity-enhancing properties, including the development and maintenance of masculine characteristics such as the growth of the vocal cords, testicles and body hair (secondary sexual characteristics).
  • The pharmacodynamic action of anabolic steroids begins when the exogenous hormone penetrates the membrane of the target cell and binds to an androgen receptor located in the cytoplasm of that cell.
  • Different types of anabolic steroids bind to the androgen receptor with different affinities, depending on their chemical structure.
  • Some anabolic steroids such as methandrostenolone bind weakly to this receptor in vitro, but still exhibit androgenic effects in vivo.