Androstadienol, or androsta-5,16-dien-3β-ol, is a

16-androstene 16-Androstenes, or androst-16-enes, are a class of endogenous androstane steroids that includes androstadienol, androstadienone, androstenone, and androstenol, which are pheromones. Some of the 16-androstenes, such as androstenone and androste ...

class endogenous steroid,

pheromone A pheromone () is a secreted or excreted chemical factor that triggers a social response in members of the same species. Pheromones are chemicals capable of acting like hormones outside the body of the secreting individual, to affect the behavio ...

, and chemical intermediate to several other pheromones that is found in the

sweat Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals. Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distrib ...

of both men and women. Androstadienol and

androstadienone Androstadienone, or androsta-4,16-dien-3-one, is a 16-androstene class endogenous steroid that has been described as having potent pheromone-like activities in humans. The compound is synthesized from androstadienol by 3β-hydroxysteroid dehydr ...

are odorless compounds secreted by the apocrine glands, and via conversion into the more powerfully-odorous androstenone and

androstenol Androstenol, also known as 5α-androst-16-en-3α-ol (shortened to 3α,5α-androstenol or 3α-androstenol), is a 16-androstene class steroidal pheromone and neurosteroid in humans and other mammals, notably pigs. It possesses a characteristic musk ...

(catalyzed by

aerobic Aerobic means "requiring air," in which "air" usually means oxygen. Aerobic may also refer to * Aerobic exercise, prolonged exercise of moderate intensity * Aerobics, a form of aerobic exercise * Aerobic respiration, the aerobic process of cel ...

corynebacteria ''Corynebacterium'' () is a genus of Gram-positive bacteria and most are aerobic. They are bacilli (rod-shaped), and in some phases of life they are, more specifically, club-shaped, which inspired the genus name (''coryneform'' means "club-shape ...

, particularly '' Corynebacterium xerosis'', in men, and '' Micrococcaceae spp.'' in women), are considered to be mainly responsible for the "musky" component of

axilla The axilla (also, armpit, underarm or oxter) is the area on the human body directly under the shoulder joint. It includes the axillary space, an anatomical space within the shoulder girdle between the arm and the thoracic cage, bounded superior ...

ry (underarm) odor. Androstadienol is synthesized from

pregnenolone Pregnenolone (P5), or pregn-5-en-3β-ol-20-one, is an endogenous steroid and precursor/ metabolic intermediate in the biosynthesis of most of the steroid hormones, including the progestogens, androgens, estrogens, glucocorticoids, and mineraloc ...

by the 16-ene-synthetase activity of

CYP17A1 Cytochrome P450 17A1 (steroid 17α-monooxygenase, 17α-hydroxylase, 17-alpha-hydroxylase, 17,20-lyase, 17,20-desmolase) is an enzyme of the hydroxylase type that in humans is encoded by the ''CYP17A1'' gene on chromosome 10. It is ubiquitously exp ...

, and is converted into androstadienone by 3β-hydroxysteroid dehydrogenase. Male sweat contains approximately five times as much androstenone as does female sweat, which can be explained by sex differences in androstadienol and androstadienone production. Androstadienone, which is produced from androstadienol, has been found to affect brain activity. Specifically, it has been found to activate the

hypothalamus The hypothalamus () is a part of the brain that contains a number of small nuclei with a variety of functions. One of the most important functions is to link the nervous system to the endocrine system via the pituitary gland. The hypothalamu ...

, most maximally the medial preoptic and anterior hypothalamic areas, in

heterosexual Heterosexuality is romantic attraction, sexual attraction or sexual behavior between people of the opposite sex or gender. As a sexual orientation, heterosexuality is "an enduring pattern of emotional, romantic, and/or sexual attractions" ...

women and homosexual men, but not in heterosexual men (who instead experienced hypothalamic activation in response to smelling

estratetraenol Estratetraenol, also known as estra-1,3,5(10),16-tetraen-3-ol, is an endogenous steroid found in women that has been described as having pheromone-like activities in primates, including humans. Estratetraenol is synthesized from androstadienone ...

, an

estrogen Estrogen or oestrogen is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal ac ...

-related pheromone, while heterosexual women and homosexual men did not). It has also been found to activate the anterior area of the inferior lateral

prefrontal cortex In mammalian brain anatomy, the prefrontal cortex (PFC) covers the front part of the frontal lobe of the cerebral cortex. The PFC contains the Brodmann areas BA8, BA9, BA10, BA11, BA12, BA13, BA14, BA24, BA25, BA32, BA44, BA45, BA46 ...

, the superior temporal cortex, and olfactory areas. The affected brain areas are thought to be involved in

sexual behavior Human sexual activity, human sexual practice or human sexual behaviour is the manner in which humans experience and express their sexuality. People engage in a variety of sexual acts, ranging from activities done alone (e.g., masturbation) t ...

, attention, visual perception/recognition, and

social cognition Social cognition is a sub-topic of various branches of psychology that focuses on how people process, store, and apply information about other people and social situations. It focuses on the role that cognitive processes play in social interacti ...

References

{{Steroid hormones Androstanes Human pheromones Mammalian pheromones Neurosteroids

See also

References