16-Androstenes, or androst-16-enes, are a class of endogenous androstane steroids that includes androstadienol, androstadienone, androstenone, and androstenol, which are pheromones. [1] Some of the 16-androstenes, such as androstenone and androstenol, are odorous, and have been confirmed to contribute to human malodor. [2]
The 16-Androstene steroid is most commonly found and produced in boar testicle, specifically in un-castrated male pigs, which results in a foul odor. [3] This foul odor typically has a urine-like or skatole odor which is as a result of high concentration and levels of the 16-Androstene steroid found in the boar's Adipose tissue, that is observed when the boar fat is cooked on heat. [3] [4] The 16-Androstene acts as a pheromone which is transported in a boar's body through the bloodstream to the salivary glands and is metabolized in the liver which produces alpha and beta-androstenol. [4] The reason why the 16-Androstene steroid is essential in the overall population of boars is because it plays a vital role in the mating process, specifically attracting gilts. [4] The 16-Androstene steroid is a vital steroid to study in order to better understand varying genes and metabolic pathways and its relation to the similarities and differences observed in human axillary odors.
The 16-Androstene steroid is a compound of interest in various research relating to the topic of steroid-based malodour. Most of the research conducted on the 16-Androstene steroid is done by experimentation of boars, often looking at various metabolic pathways and genetics which are similar and different in varying breeds of boars. [4] These studies are conducted in order to utilize the research conducted on boars to better understand human axillary odors. Research conducted by Gower in 1994 suggested that the 16-Androstene along with other steroids such as the 5α-androstenol and 5α-androstenone, are prevalent in apocrine sweat glands. [5] Later research by Austin and Ellis in 2003 revealed through the use of mass spectrometry (MS) and gas chromatography (GC), that the 16-Androstene steroid was present on axillary skin which determined that axillary bacteria are able to create 16-androstenes steroids from the bacteria that had the C16 double bond already present. [5] Other research indicates that 3[beta]-hydroxysteroid dehydrogenase (3[beta]-HSD) plays a vital role in the metabolism of androstenone. [4] When looking at the adipose tissue of a boar, it was also observed that there were high levels of androstenone when there was a low expression of enzymes, protein and mRNA showing a negative trend. [4] Additionally, some research indicates that the presence of the 16-Androstene steroid contributes significantly to the role and function of the liver which is to participate in phase II conjugation metabolism. [3] These were some of the research findings from various articles illustrating the role that the 16-Androstene steroid plays in metabolic pathways and genetics. All of these research findings are able to assist in better understanding genes, metabolic pathways, and enzymes which will aid in scientists understanding how to diminish boar taint / odor.
A variety of research methods were utilized in multiple research articles to gather vital information on the 16-Androstene steroid. Methods such as PCR, mass spectrometry (MS), gas chromatography (GC), solid-phase chromatography, microarray technology, and various other methods were utilized in the research articles to understand the 16-Androstene steroid.
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 behavior of the receiving individuals. There are alarm pheromones, food trail pheromones, sex pheromones, and many others that affect behavior or physiology. Pheromones are used by many organisms, from basic unicellular prokaryotes to complex multicellular eukaryotes. Their use among insects has been particularly well documented. In addition, some vertebrates, plants and ciliates communicate by using pheromones. The ecological functions and evolution of pheromones are a major topic of research in the field of chemical ecology.
Androsterone, or 3α-hydroxy-5α-androstan-17-one, is an endogenous steroid hormone, neurosteroid, and putative pheromone. It is a weak androgen with a potency that is approximately 1/7 that of testosterone. Androsterone is a metabolite of testosterone and dihydrotestosterone (DHT). In addition, it can be converted back into DHT via 3α-hydroxysteroid dehydrogenase and 17β-hydroxysteroid dehydrogenase, bypassing conventional intermediates such as androstanedione and testosterone, and as such, can be considered to be a metabolic intermediate in its own right.
Dihydrotestosterone is an endogenous androgen sex steroid and hormone primarily involved in the growth and repair of the prostate, the production of sebum, and body hair composition.
Body odor or body odour (BO) is present in all animals and its intensity can be influenced by many factors. Body odor has a strong genetic basis, but can also be strongly influenced by various factors, such as gender, diet, health, and medication. The body odor of human males plays an important role in human sexual attraction, as a powerful indicator of MHC/HLA heterozygosity. Significant evidence suggests that women are attracted to men whose body odor is different from theirs, indicating that they have immune genes that are different from their own, which may produce healthier offspring.
Androstenone (5α-androst-16-en-3-one) is a 16-androstene class steroidal pheromone. It is found in boar's saliva, celery cytoplasm, and truffle fungus. Androstenone was the first mammalian pheromone to be identified. It is found in high concentrations in the saliva of male pigs, and, when inhaled by a female pig that is in heat, results in the female assuming the mating stance. Androstenone is the active ingredient in 'Boarmate', a commercial product made by DuPont sold to pig farmers to test sows for timing of artificial insemination.
Metandienone, also known as methandienone or methandrostenolone and sold under the brand name Dianabol (D-Bol) among others, is an androgen and anabolic steroid (AAS) medication which is still quite often used because of its affordability and effectiveness for bulking cycles. It is also used non-medically for physique- and performance-enhancing purposes. It is often taken by mouth.
Androstenol, also known as 5α-androst-16-en-3α-ol, is a 16-androstene class steroidal pheromone and neurosteroid in humans and other mammals, notably pigs. It possesses a characteristic musk-like odor.
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 dehydrogenase, and can be converted into androstenone by 5α-reductase, which can subsequently be converted into 3α-androstenol or 3β-androstenol by 3-ketosteroid reductase.
Epiandrosterone, or isoandrosterone, also known as 3β-androsterone, 3β-hydroxy-5α-androstan-17-one, or 5α-androstan-3β-ol-17-one, is a steroid hormone with weak androgenic activity. It is a metabolite of testosterone and dihydrotestosterone (DHT). It was first isolated in 1931, by Adolf Friedrich Johann Butenandt and Kurt Tscherning. They distilled over 17,000 litres of male urine, from which they got 50 milligrams of crystalline androsterone, which was sufficient to find that the chemical formula was very similar to estrone.
5α-Androst-2-en-17-one is an endogenous, naturally occurring, orally active anabolic-androgenic steroid (AAS) and a derivative of dihydrotestosterone (DHT). It is a metabolite of dehydroepiandrosterone (DHEA) in the body and is also a pheromone found in elephants and boars. 5α-Androst-2-en-17-one has been sold on the Internet as a "dietary supplement". It resembles desoxymethyltestosterone (17α-methyl-5α-androst-2-en-17β-ol) in chemical structure and may act as an androgen prohormone.
3β-Androstanediol, also known as 5α-androstane-3β,17β-diol, and sometimes shortened in the literature to 3β-diol, is an endogenous steroid hormone and a metabolite of androgens like dehydroepiandrosterone (DHEA) and dihydrotestosterone (DHT).
Androstadienol, or androsta-5,16-dien-3β-ol, is a 16-androstene class endogenous steroid, pheromone, and chemical intermediate to several other pheromones that is found in the sweat of both men and women.
3β-Androstenol, also known as 5α-androst-16-en-3β-ol, is a naturally occurring mammalian pheromone known to be present in humans and pigs. It is thought to play a role in axillary odor. It is produced from androstenone via the enzyme 3β-hydroxysteroid dehydrogenase. Unlike its C3α epimer 3α-androstenol, 3β-androstenol shows no potentiation of the GABAA receptor or anticonvulsant activity.
A xenobiotic-sensing receptor is a receptor that binds xenobiotics. They include the following nuclear receptors:
No study has led to the isolation of true human sex pheromones, though various researchers have investigated the possibility of their existence. Sex pheromones are chemical (olfactory) signals, pheromones, released by an organism to attract an individual, encourage it to mate with it, or perform some other function closely related with sexual reproduction. While humans are highly dependent upon visual cues, when in proximity, smells also play a role in sociosexual behaviors. An inherent difficulty in studying human pheromones is the need for cleanliness and odorlessness in human participants. Experiments have focused on three classes of putative human pheromones: axillary steroids, vaginal aliphatic acids, and stimulators of the vomeronasal organ.
The biochemistry of body odor pertains to the chemical compounds in the body responsible for body odor and their kinetics.
The androgen backdoor pathway is a collective name for all metabolic pathways where clinically relevant androgens are synthesized from 21-carbon steroids (pregnanes) by their 5α-reduction, bypassing testosterone and/or androstenedione.
5α-Pregnan-17α-ol-3,20-dione, also known as 17α-hydroxy-dihydroprogesterone (17‐OH-DHP) is an endogenous steroid, a metabolite of 17α-hydroxyprogesterone.