September 23, 2021

Biology Reporter

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Pheromones, a great mystery of modern science

Pheromones, a great mystery of modern science

midsummer. to heat up. Through the narrow lane, you hit the last row on the bus. A man walks several centimeters from you. You can smell it – the sweat in a linen shirt. Until now, you have imagined that such situations may cause you discomfort. This time it’s different. Take a deep breath. And one more. It amazes you. You cannot explain why.

– Pheromones! – You hear back later from your friend.


Scholars have been dividing this topic for a long time. – For every five publications confirming that humans secrete pheromones, we will find another five publications that question their existence – says the professor. Barczak.

So what are they? They are semi-chemicals, that is, substances that are used to transmit specific information to individuals of the same species.

– It must be effectively delivered to the outside, which is why pheromones are usually volatile substances that have to get out of the body somehow. This distinguishes it from the hormones that are produced and secreted within it and that only serve the producing entity. Pheromones are secreted outside the body and the “consignee” is another individual. The science that deals with hormones is endocrinology (Greek: endon – inside – ed.). A potential branch of science dealing with pheromones could be called exocrinology (Greek: exo – outside – ed.) – explains the chemist.

Its presence is well scientifically proven in insects and rodents. We know the chemical composition and effect of these substances, we can obtain them artificially and use them, for example, to protect crops. When the apple fruit destroys the fruit in the orchard, we can use the female pheromone that is ready for mating, which will effectively attract all the males in the vicinity of this insect into the trap. Interestingly, pheromone traps have already been used for more than a hundred years. Compared with other plant protection products, it is more environmental.

Organisms secrete pheromones externally, for example to arouse attraction in individuals of the opposite sex (sexual), communication (total) or for defense (hostile) purposes. Depending on the functions performed, pheromones are divided into 30 groups.

The first studies of the presence of pheromones in humans began in the early 1970s.

a. Piotr Suffczyński From the Institute of Experimental Physics at the University of Warsaw quotes the American psychologist Martha McClintock and published the results of her research in the journal “Nature” in 1971.

The phenomenon of synchronized menstrual cycles has even been dubbed the “McClintock effect.” Subsequent studies were conducted in other groups of humans, rats, hamsters, and chimpanzees. They did not conclusively confirm the researcher’s hypothesis.

In 1998 another McClintock study appeared in Nature as well.

– The woman was supposed to smell a piece of cotton soaked with perspiration from the armpits of another representative of the same sex. Subsequently, it causes significant changes in its cycle length, says Suffczyński.

Some American scholars criticized. He was accused of drawing unwarranted conclusions due to the uncertain presence of pheromones in humans.

In the early 2000s, Serbian-Swedish neuroscientist Ivanka Savic conducted similar research.

Two steroids were manufactured. One – AND (androstadienone) is present in male sweat and the other – EST (estratetraenol) is present in female urine. They were introduced to “sniff”, even though they do not smell. When the women ‘inhaled’, there was activation in an area of ​​the brain called the hypothalamus and in the amygdala responsible for behavior, emotional memory and the release of joy and euphoria but also anxiety. The same reaction is observed in the case of men “sniffing” EST. These studies were conducted in 2001. A few years later, they were repeated on gay men and women. The responses were the opposite of those seen in heterosexuals. Lesbians had a greater reaction to EST, and gays to AND. This shows that sexual orientation is conditioned at the level of the brain, and we do not acquire it – summarizes Suffczyński.

Professor Barczak draws attention to the possible relationship of human pheromones with the major histocompatibility system (MHC).

Swiss biologist Klaus Wedekind conducted in 1995 a “Sweaty t-shirt” experiment that postulated the presence of MHC and partner selection. Given the different types of MHC, he selected 49 women and 44 men. He gave the latter a clean shirt. They had to wear it for two days and then put it back. The unwashed shirts were placed in matching boxes. Women were supposed to smell themselves and decide which scent attracted them the most. The results showed that the most attractive women were the men’s T-shirts that differed the most from the MHC.

– MHC is owned by all of us. It is a group of very complex molecules that determine, among other things, whether an alien organ will be accepted or rejected in a case of cultivation. An important role in it is played by human leukocyte antigens – some of the proteins that determine how our bodies react to foreign cells. What does it show? That the set of these proteins can be responsible for an individual set of odors (both palpable and imperceptible), characteristic only of us. Something like fingerprints, but it’s related to the sense of smell. It may turn out that our “perfume profile” – on a subconscious level, of course – will seem more attractive to a person. This is because two different and complementary MHCs can provide better health and strength for our offspring. So it is best to mate with someone who has an MHC supplement for us. Perhaps that’s why some people’s scents attract us more. Are these pheromones? We don’t know, because in fact – if humans exist – we still don’t have a clear enough answer.

So, as humans, will we be able to feel them? A potential Jacobson organ, also known as a throat organ, may be responsible. It is found in many animals and is used to detect volatile chemicals. In reptiles, it is the main organ of the sense of smell.

In humans, this organ develops in the embryonic stage, at the end of the first trimester of pregnancy, at the base of the nasal septum. It is still active in newborns, but at a later stage of development it is likely that its activity will disappear – but this has not been sufficiently researched so far.

– If the activity of Jacobson’s organ does not actually disappear in adults, then it fits perfectly with the theory of the existence of human pheromones, because he would be able to detect them – says Barczak.

Suffczyński cites the story of Oliver Sacks, an American neurologist. In one of the chapters of the book “The Man Who Sinned His Wife for a Hat” he describes the case of Stephen.

– At night he dreamed that he was a dog. Upon awakening, his sense of smell began to dominate the rest. The man did not recognize the world by images or other stimuli, but by smell. Within weeks, he lost this ability, which was his loss and his relief. In subsequent years, Sachs admitted that Stephen’s story was his own experience after drug use. Fearing harming his career, he did not reveal it sooner. Ethics is as follows. We perceive olfactory signals all the time, but – most likely – we don’t consciously process them. Perhaps because we have developed other senses that the brain considers more important.

When writing about pheromones, it is impossible not to mention perfumes with their addition. There are many such products on the market in the price range from several tens to several hundred zlotys. Manufacturers guarantee success in the opposite sex, increased libido, success in business or in social contacts. However, they often cite parts of the research results out of context and repeat misinformation or – at least – unconfirmed (such as the fact that scent pheromones and Jacobson’s organ are actually active in adults).

The composition of the product often includes androstadienone, which Ivanka Savic was interested in. Recall – there is no consensus among scientists regarding its recognition as a human pheromone.

I don’t really believe in the efficacy of this perfume. If you find human pheromones, it is rather a multicomponent mixture of different chemicals – and it is still unknown. In addition, this mixture can be individual for each of us, so it is impossible to create a single universal pheromone or “mixture” that affects everyone around us – explains Barczak.

– To treat them scientifically, you must know what they contain – adds Suffczyński.

“There is no reason to assume that human pheromones do not exist, but we still have little information to confirm this and the real role they may play. The results of various experiments put forward research hypotheses regarding the existence of contact between people based on pheromones, but they do not identify the chemicals responsible for this. In insects, isolation of such substances was much simpler because the stimulus-response coupling (ie a particular chemical has a specific effect) is less complex than in humans. Man is the most advanced form of life we ​​know of, and to think of human communication in a simple category – at least – is unfortunate.

In science, one answer generates the following ten questions. I am currently teaching quantum mechanics. In the space of a few years, it turned everything that scientists had collected for three centuries upside down. The same can happen with pheromones. The fact that we don’t know much about them yet, doesn’t mean we should stop the research – the UMCS chemist thinks.

However, in his opinion, we will not achieve certainty in the near future.

Moreover, if I were to be relatively betting on developing an effective vaccine or fighting cancer, and identifying pheromones, we know what the priority would be, Barczak concludes.

And when you’re on the bus again amazed by the smell of another man, maybe it’s not worth looking for the answer in chemical formulas?

The subconscious mind and its mechanisms are crucial to our work. If we want to recognize and define this attraction, we are doomed – adds Suffczyński.

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