5a-Androst-2-en-17-one

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. 

The well-known boar pheromone was not only one of the first mammalian pheromones identified, but also the first one applied commercially. The saliva from the submaxillaiy gland contains two steroids. These are 5a-androst-16-en-3-one and So -androst-lS-en-So -ol (Fig. 7.8). They are emitted during head-to-head contact in courtship. Both individually stimulate the sow to assume the mating stance, but a mixture of the two is not more active than either compound (Melrose etal., 1971). This may be a case of adaptive redundancy. 

Amoore, J. E., Pelosi, P., and Forrester, L. J. (1977). Specific anosmias to 5a-androst-16-en-3-one and primary odors. Chemical Senses and Flavour 1,401-425. 

Virtually all people lack the ability to detect some specific odors. A striking example of such an anosmia is the inability to smell the volatile steroid androsten-one (5a-androst-16-en-3-one), a constituent of perspiration, of some pork products, truffles, and celery.922... 

Tritium-labelled 3/ -acetoxy-[5a,6a-3H]-5a-androstan-17-tosylhydrazone (44) has been prepared as an intermediate in a four-step synthesis41 of the hormone [5a,6a-3H]-5a-androst-16-en-3-one(45), starting from 3jS-acetoxyandrost-5-en-17-one (46, equation 20). Product 45 has been applied in radioimmunoassay determinations of 5a-androstenone in biological systems. 

But men also have their chemical appeal. Their 5a-androst-16-en-3-one and androsta-4,16-dien-3-one act as attractants for women. Tests have been carried out, whereby it was observed that women - without being aware of their selection - prefer to sit on chairs, which have been doped with these substances. 

Truffles are highly esteemed, subterranean mushrooms, which can be retrieved by sexually mature sows, because they emit traces of 5a-androst-16-en-3-one. [15]... 

Men also have chemical stimulants. [14] Prelog and Ruzicka resolved the structure of 5a-androst- 16-en-3-one, the sex pheromone ofthe boar Sus scrofa domestica), [15] and, as it became clear later, also of men. [16] It is a metabolite of testosterone and its odour was described as a scent of receptacles , which had been used over a longer period to store urine. In waiting rooms, women preferred to sit rather on androstenone-impregnated chairs than on those which were untreated. Also, photographs of men, animals and houses primed with traces of 5a-androst- 16-en-3-one were considered more warm and friendlythan those which lacked the boar pheromone. 

The so-called "pheroboa/ "(referring to an aerosol spray) - a pheromone preparation consisting of a mixture of 5a-androst-16-en-3-one and 5a-androst-16-en-3-ol - Is used In veterinary medicine and by pig farmers to stimulate sows prior to artificial Insemination.The pheromone Induces the release of oxytocin, which leads to contraction ofthe Fallopian tube and the uterus, and thereby Increases the conception rate. [12]... 

It was most timely that the only known mammalian semiochemicals which fit nicely into the concept of insect pheromones - two steroids present in the saliva of the domestic boar (5a-androst-16-en-3-one and 3a-hydroxy-5a-androst-16-ene) - were isolated by Patterson (1969), just at the time when interest in olfactory communication was rising. 

Bird, S., and Gower, D. B., 1980, Measurement of 5a-androst-16-en-3-one in human axillary secretions by radioimmunoassay, J. Endocrinol., 85 8P. 

Bird, S., and D.B. Gower Estimation of the Odours Steroid, 5a-Androst-16-en-3-one, in Human Saliva. Experientia 39, 790-792 (1983). 

Certain androstene derivatives are male sex hormones in higher animals (E 3.1). The most important ones in man are androstenedione and testosterone, which are produced in the testes. In the target tissues, e.g., the prostate gland testosterone is reduced to 5a-androstane-17 -ol-3-one, which seems to be the real metabolic effector. The androstenedione and testosterone that accumulate in certain plant cells, e.g., in the pollen of Pinus sylvestris probably have an ecological function (E 5.5.3). 5a-Androst-16-en-3-one and 5a-androst-16-en-3 x-ol are sex pheromones of the boar (E 4). 5oc-Androst-16-en-3-one is also a constituent of human urine (the urine of males containing three times the concentration of the urine of females) and 5a-androst-16-en-3oc-ol was shown to occur in the sweat of male humans. 

Part of the population suffers from so-called specific anosmia (specific olfactory blindness), which is manifested by an inability to perceive certain odours. About 100 substances are known that are not perceived by a limited number of human beings. For example, 70.5% of women and 62.8% of men reportedly perceive (5a)-androst-16-en-3-one, while the scents of cloves and bananas are perceived by nearly 100% of the population. About 1.2% of the total population suffer from total anosmia, which is a condition in which people have no sense of smell. People with anosmia... 

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