Androstenone

Dana2ol was prepared from 4.32 grams of 17a-ethynyl-2-hydroxymethylene-4-androsten-17(3-ol-3-one, 1.00 gram of hydroxylamine hydrochloride, 1.12 grams of fused sodium acetate and 135 ml of acetic acid. To a 500 ml, 3-necked flask, equipped with a sealed Hershberg-type stirrer, a reflux condenser and a stopper, was added the above androstenone derivative in 300 ml of 95% ethanol. Stirring was commenced and a slurry of fused sodium acetate and hydroxylamine hydrochloride in glacial acetic acid was added. 

Dorries K.M., Adkins-Regan E. and Halpem B.P. (1995). Olfactory sensitivity to the pheromone, androstenone, is sexually dimorphic in the pig. Physiol Behav 57, 255-259. 

Domes, K. M., Adkins Regan, E. and Halpem, B. P. (1997) Sensitivity and behavioural responses to the pheromone androstenone are not mediated by the vomeronasal organ in domestic pigs. Brain Behav. Evolut. 49, 53-62. 

Kirk-Smith, M. and Booth, D.A. (1980) Effects of androstenone on choice of location in others presence. In H. van der Starre (Ed), Olfaction and Taste VII. IRL Press, London, pp. 397-400. 

Not only the sensitivity of the human olfactory system to androstenol (5a-androst-16-en-3a-ol) and androstenone (5a-androst-16-en-3-one),but also the difference in the sensitivity with which individuals can detect these compounds and the fact that they are implicated in the semiochemical communication of the pig, Sus scrofa [166,167], have led to them being considered human pheromones. Final confirmation that they are human pheromones is still outstanding. However, it was recently found that passive inhalation of another related steroid, androsta-4,16-dien-3-one, can influence the physiological state of humans by increasing a positive mood in test persons [168]. It has yet to be determined whether humans exude concentrations of this chemical information that are adequate for communication within social contexts. 

Here is a bit of a complication there is a lot of individual variation in the sense of human olfaction. Not everything smells the same to everyone. This holds both for the intensity of the perceived smeU as well as for its quality pleasant, floral, skunky, sweaty, or no odor at all. Andreas Keller has recently demonstrated that some significant part of this individual variation in the sense of smell derives from genetic variation in human odorant genes. Specifically, two single nucleotide polymorphisms (SNPs), leading to two amino acid substitutions in an odorant receptor, have dramatic affects on the perception of the odor of androstenone, a steroid derived from testosterone. 

In some cases, commercial use has been made of reproductive pheromonal effects. For example, spraying sows with synthetic 5a-androstenone, a steroid sold under the trade name Boar Mate, helps to ready the animal for mating with a boar. 5a-Androstenone is one of two steroids in the saliva of the boar that primes the sow for mating. 

In contrast to the evidence for primers, signalers, and modulators, there is no decent evidence to suggest that there are human releaser pheromones. That is not to argue that there are none but to state that there is no evidence for them at present. Nonetheless, products purported to be human releaser pheromones—specifically sex attractants—are widely available on the Internet. They go by such suggestive names as Scent of Eros, The Edge, Alter-ego, and Pheromone Additive. Many of these products contain either androstenone or androstenol, steroids of unknown influence on the human emotional state. 

Saliva may also contain specific chemical information for individual recognition (Blass and Teicher, 1980) or kin recognition (Block etah, 1981 Smith and Block, 1990). The best-known example of a salivary pheromone is the mixture of androstenone and androstenol in the submaxillary glands of the boar. 

In some mammals, the sexes differ in their odor thresholds. The sow detects the boar pheromone androstenone (5o -androsten-16-en-3-one) easily at 3.67 x 10 mol/l, while this concentration is near or below the threshold for boars. Boars initially could not detect the odor at all but became more sensitive after repeated exposure (Dorries etal, 1991). 

Male odor accelerates puberty in the domestic pig. The two steroids 5a-androstenone (5o -androst-16-en-3-one) and 3a-androstenol (5o -androst-16-en-3-ol) play a role in this effect (Booth, 1984). 

The boar sex pheromone, consisting of androstenol and androstenone, from the submaxillary salivary gland has been used commercially for artificial insemination of pigs. It was available as a spray under the trade name Suidor (formerly Jeyes Boar Mate) in Europe (Glei etal, 1989). Sows who did not assume the... 

For most specific anosmias the individual differences represent a concentration effect that is anosmic individuals will recognize the odor at some higher level of exposure. However, in the case of an stenone, individuals d it either unpleasant (urinous, sweaty), pleasant (floral, musky) or odorless, independent of the concentration. Surprisingly, the anosmia can be reversed in some individuals through constant exposure (57). Anosmic subjects exposed to androstenone three times per day (3 minutes) over a 6 week period became osmic to it A substantial decrease in threshold (i.e. increased sensitivity) was found for 10 of 20 subjects. 

In addition to conjugated dienes, cyanocobalt catalysts also hydrogenate the C=C bond of activated alkenes.52 Carvene, mesityl oxide, 2-cyclohexenone, benzalacetone and an androstenone derivative were reduced in this way.53... 

It is not always the female that gives off pheromones. The musk male deer attracts his mate by means of the chemical muscone which he releases from a special gland, and male pigs emit androstenone which turns female pigs on. Humans also produce this molecule in their armpits, males especially so, and it has a very faint musky odour. Could it attract women Some men believe it could and sex shops sell this chemical in spray form. There is as yet no scientific evidence that it is a human pheromone, but there are suggestions that we may detect and respond to molecules even though we cannot smell them. 

In 1986 the largest ever smell survey was carried out involving 1.5 million people from all over the world. They were given scratch and sniff cards and a questionnaire to answer. The scents tested were androstenone, isoamyl acetate (banana), glaxolide (a synthetic musk), eugenol (cloves), rose, and a mercaptan (the one added to natural gas to make it detectable). Of those who took part, 50% were able to detect all six smells and only 1% could detect none of them. Women were found to be better than men. The smell that was sensed the least was androstenone, and if this really is a human pheromone then it does not operate by having an irresistible odour. 

The chief culprits in generating armpit odours are the bacteria Corynebacterium xerosis and Micrococcus luteus, with Staphylococcus epidermis and Staphylococcus aureus playing minor roles. There can be as many as ten million bacteria cells per square centimetre of armpit skin compared to only 1,000 on the skin of the forearm, and this is as true for women s armpits as for men s, and yet the odour women give off is different because it lacks some of the ingredients that male sweat contains. Male underarm odour has three components an acrid one, a musky one, and a pungent one. The first of these comes from short-to-medium chain acids, the second from steroid type molecules, and especially androstenone, and the third from sulfur-containing molecules. 

Another reason for the relative lack of interest in mammalian pheromones lies in the fact that - apart from the use in perfumes - only one actual application of mammalian pheromones is known so far. This is not in connection with a pest but with a very useful animal, the domestic pig (5). The saliva and sweat glands of the sexually aroused boar contain two steroids with a musky smell, A16 androstenol and A16-androstenone. These are actual pheromones emitted by the male and eliciting a characteristic behaviour in the female. Sows in heat react to the scent of these compounds by assuming a characteristic copulating stance. 

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