Pheromones are scents that influence the behavior of conspecifics. For humans, mainly sex pheromones are known in this regard. Thus, for example, the pheromones of the man have an influence on the menstrual cycle of the woman.
What are pheromones?
Pheromones are messenger substances. They are used for nonverbal, purely chemical communication between individuals of a species. In this respect, pheromones can also be called semiochemicals. The body of the sender secretes them unconsciously and automatically. The receiver perceives them unconsciously and gives a behavioral response to them. The chemist Karlson and the zoologist Lüscher coined the term pheromones in the 20th century as chemical substances that trigger specific reactions in a conspecific. The best known pheromones are sex attractants. However, even apart from these, there are different types of the biochemical substances. Aggregation pheromones, dispersion pheromones, alarm substances, trace pheromones or markers, and aphrodisiac pheromones are among the most important groups. Among humans, however, most of them are not common. For them, only the sex attractants play an increased role among the pheromones. In German, there is a saying that the chemistry between two people is right or wrong. This saying relatively aptly reflects the function of sex pheromones.
Anatomy and structure
Each pheromone is either a primer or a release pheromone. Primer pheromones trigger a signaling cascade. Thus, they influence metabolism or even stimulate proteins that bind to DNA. They thus trigger a physiological change in the recipient. Releaser pheromones, on the other hand, have only a brief effect, controlling the behavior of a conspecific. Humans have only primer pheromones. The best known of these are formed in the axial glands of the male. All pheromones are released through the sebaceous and sweat glands of the skin, through bacterial strains or urine, saliva and vaginal secretions. Each pheromone is structured in such a way that it can attach itself to the cilia in the olfactory organ of its conspecific. Thus the structure and of pheromones differs with the species. The structure of the substances also differs with the respective function. For example, the resus monkey emits as a sex attractant a mixture of acetic, butyric, propionic, isovaleric and isobutyric acids. The dog, on the other hand, produces methyl p-hydroxybenzonate as a sex attractant. So far, the structure of pheromones has been further researched only for insects.
Function and tasks
Pheromones perform various communication functions within a species. The exchange of information refers either to individuals within the respective species or to those of foreign species. Sex attractants or such pheromones for territory marking, for example, provide information about individuals of their own species. Alarm substances, on the other hand, often refer to dangers from outside. For example, living organisms can warn different conspecifics of invading aliens. For example, the black-tailed deer uses the pheromone cis-4-hydroxy-dodec-6-ene-acid lactone to alert other black-tailed deer. The mouse, on the other hand, has pheromones to accelerate puberty, but also those to trigger aggression. The maturational effects of some neurotransmitters are in turn related to the interconnectedness of hormones and pheromones. Some animal species also mimic the pheromones of other species in order to join their ranks. Butterfly caterpillars, for example, mimic the behavior-influencing pheromones of ants in order to be fed by them. They are thus falsely recognized by the ants as brood. In humans, sex pheromones influence perception in the opposite sex. Androstadienone is found for this purpose, for example, in the seminal fluid and armpits of a man, while a woman secretes estratetraenol. Homosexuals react to the messenger substances of their own sex in this context. The male sex attractant can influence a woman’s menstrual cycle, which apparently serves to increase the birth rate. Secretions from the female vagina and armpits have even been shown to have dream-modulating effects on men during deep sleep. Among humans, pheromones are unconsciously absorbed by the olfactory system and thus influence the autonomic or hormonal system via automatic responses of the brain, without the person even noticing this influence.
Diseases
In humans, a change in pheromone balance is usually reflected in changes in hormone balance. An altered hormone balance can result in various symptoms. Among the most important are fatigue, lack of drive and obesity, but sexual dysfunction can also be due to hormone deficiency. In women, hormonal and pheromone imbalances also often result in menstrual cramps. However, not all changes in the pheromone balance are equally pathological. Many changes are biologically intended, for example those during menopause or pregnancy. According to recent studies, the altered pheromone balance of pregnant women should have an effect on their own behavior as well as on the behavior of their partner. These changes in pheromone levels are said to be able to trigger, for example, the so-called couvade syndrome, which is also known to affect brood care behavior. Not all hormonal changes have the same origin in altered pheromone production. Diseases such as diabetes or thyroid disorders can also have an influence on the hormone balance. In medicine, it is currently being discussed whether the administration of certain pheromones in the context of various diseases could serve therapeutic purposes. So far, however, the pheromone processes in humans have not been sufficiently researched to provide a satisfactory answer to this question.