Hair, androgens

In women receiving an androgen preparation for breast carcinoma, the most common adverse reactions are amenorrhea, other menstrual irregularities, and virilization (acquisition of male sexual characteristics by a woman). Virilization produces facial hair, a deepening of the voice, and enlargement of the clitoris. Male pattern baldness and acne may also be seen. 

Loss of axillary and pubic hair in women owing to decreased androgen production... 

Excessive hair growth (hirsutism) and acne also may be present owing to relative androgen excess compared with low estrogen levels. 

Presence of acne, hirsutism, hair loss, or acanthosis nigricans may suggest androgen excess. 

Sebum is released by the sebaceous glands and naturally maintains hair and skin hydration. An increase in androgen levels, especially during puberty, can cause an increase in the size of the sebaceous gland and the production of abnormally high levels of sebum within those glands. This excess sebum can result in plugged follicles and acne formation. 

This drug reduces the growth of facial hair in idiopathic hirsutism or hirsutism that is secondary to androgen excess... 

Testosterone is the most important of the male sexual steroids (androgens), it is synthesized in the Leydig intersitial cells of the testes, and controls the development and functioning of the male gonads, it also determines secondary sexual characteristics in men (muscles, hair, etc.). 

Pharmacologic doses in women stimulate growth of facial and body hair and produce deepening of the voice, enlargement of clitoris, frontal baldness and prominent musculature. Natural androgens stimulate erythrocyte production. 

Topical minoxidil is effective in reversing the progressive miniaturization of scalp hairs associated with androgenic alopecia (male pattern baldness). It is a hereditary disorder due to excessive conversion of testosterone to dehydrocorticosterone in the scalp skin in genetically susceptible men. 

It is a inhibitor of 5-alpha reductase and blocks the conversion of testosterone to dehydrotesto-sterone. It prevents further hair loss in the significant proportion of men in the androgenic alopecia. 

Spironolactone is also an androgen antagonist and as such is sometimes used in the treatment of hirsutism in women. Dosages of 50-200 mg/d cause a reduction in the density, diameter, and rate of growth of facial hair in patients with idiopathic hirsutism or hirsutism secondary to androgen excess. The effect can usually be seen in 2 months and becomes maximal in about 6 months. 

Topical minoxidil (Rogaine) is effective in reversing the progressive miniaturization of terminal scalp hairs associated with androgenic alopecia. Vertex balding is more responsive to therapy than frontal balding. The mechanism of action of minoxidil on hair follicles is unknown. Chronic dosing studies have demonstrated that the effect of minoxidil is not permanent, and cessation of treatment will lead to hair loss in 4-6 months. Percutaneous absorption of minoxidil in normal scalp is minimal, but possible systemic effects on blood pressure (see Chapter 11) should be monitored in patients with cardiac disease. 

Finasteride (Propecia) is a 5K-reductase inhibitor that blocks the conversion of testosterone to dihydrotestosterone (see Chapter 40), the androgen responsible for androgenic alopecia in genetically predisposed men. Oral finasteride, 1 mg/d, promotes hair growth and prevents further hair loss in a significant proportion of men with androgenic alopecia. 

The androgens stimulate the development of the male secondary structures, such as the penis, scrotum, seminal vesicles, prostate gland, vas deferens and epididymis. The deepening of the voice, the growth of pubic, axillary, body, and facial hair, as well as the development of the characteristic musculature of the human male, are also under the influence of testosterone. If the testes fail to develop or are removed prior to puberty, these changes do not occur. Thus, testosterone is essential for reproductive function of the male. 

Male Hormones. The androgenic hormones produced in Ihe testes land adrenal gland t have a w idespread effect upon the development of secondary sexual characteristics (musculature, facial hair, larynx, etc. I. as well as upon the sexual organs and responses themselves. They also promote anabolism tu a marked degree by their effect upon nitrogen and calcium metabolism. The structure of testosterone is shown in the Tahle I. 

Hirsutism is common in patients taking androgens, and is often irreversible (62,63). In contrast, in women, loss of scalp hair can occur (64). Of 81 female-to-male transsexual subjects, mean age 37 years (range 21-61), treated with testosterone esters (n = 61 250 mg intramuscularly every 2 weeks) or testosterone undecanoate (n = 20 160-240 mg/day orally), 31 developed male-pattern baldness thinning of the hair was related to the duration of androgen administration and was present in about half of the transsexuals after 13 years (65). 

Secondly, androgenic characteristics or effects which are commonly referred to as secondary male characteristics that promote sexual behavior, libido, development and maturing of the penis, body hair, beard growth, deeper voice, aggressiveness, and formation and maturation of sperm. And of course, as any pubescent boy will tell you, increased production of the sebaceous gland and pimples. 

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