Hormones-feeders are responsible for providing the body with energy and all necessary substances for life. They cause feelings of hunger and satiety, control food behavior. Those hormones that suppress appetite (“anti-feeders”), were included in the conditional group of feeders for convenience, in order not to have to divide this Chapter into two. “Breadwinners” and “anti-feeders” are better considered in a complex. The thing is, in fact, they do the same, but they have different approaches.
“Love and hunger rule the world… “said the German poet Schiller in the closing lines of his poem with the pretentious title”world wisdom”.
In the opinion of the physiologist, this statement sounds wrong. Hunger had to be put in the first place, because this feeling is much more important for the body than love. At least because it is primary – normally the body first needs to satisfy hunger, and then think about love.
However, in female mammals in the regulation of hunger and satiety, that is – in the formation of eating behavior, participate sex hormones. Note-do not” regulate “and do not” form”, and”participate”.
In women during the menstrual-ovarian cycle significantly changed diet and body weight (“significantly” in relation to body weight means plus 2% and more of the weight). Change in the absence of any “external” reasons, purely for internal reasons. In men, these indicators remain stable.
In estrogens and first of all-in estradiol. More precisely-in the change of its production during the cycle (see chart).
Estrogens have the ability to suppress appetite. And this property is quite well expressed. Not to such an extent, of course, that any woman of reproductive age would not have to be afraid to gain weight, but still – to a large extent. Otherwise, we would not mention it here, because we are not talking about everything-everything-everything, but only about the most important.
Would you like a percentage? Oh, it is very difficult, because there is no solid “fulcrum”, from which you can push off when comparing, and the concentration of estrogen in the blood of each woman is different and each body is susceptible to them in its own way. But if we simplify and “avoid” (i.e., not too much to go into detail, and take the average value), we can say that the appetite suppression by estrogens in women of reproductive age is 20-30% of “srednego appetite” (don’t look for the term “credeasi appetite” in the search engines and don’t ask about it in nutritionists, because its just made up by the author, solely in order to give you an idea of the effect of estrogen on appetite).
We are talking about the suppression of appetite estrogens only in women of reproductive age, because women in the postmenopausal period and men throughout life estrogens are produced in the wrong quantities to suppress appetite. One of the reasons for weight gain in the postmenopausal period is a decrease in estrogen production in the body and the dominance of a weaker hormone than estradiol, estrogen.
However, men should not feel deprived. But this will be discussed later, first we need to deal with estrogens. Once and for all.
No, you just think – estrogens stimulate the deposition of fat in the lower abdomen, buttocks and hips, the same fat, which has the ability to synthesize estrogens (“friendly” relationship is obvious!), but estrogens suppress appetite! Where is the logic? Fat is not taken “out of the air”, that is – by itself. Nothing is formed in the body of anything, despite the fact that many believe it. Fat formation requires fatty acids, glycerin and a certain amount of energy. The hormone that stimulates the formation of fat, should simultaneously provide the body with the necessary resources, so it will be logical and correct. Estrogens should be consistent in their actions, and not to show a kind of”metabolic voluntarism.”
But what is, is. Estrogens suppress appetite and therefore in the follicular phase of the menstrual-ovarian cycle, which begins on the first day of menstruation and lasts until ovulation, women of reproductive age experience less appetite than in the luteal phase, which begins after ovulation. In the follicular phase, the production of estrogens increases, by the time of ovulation, their content in the blood reaches its peak, and then decreases. Progesterone, which “rules the ball” in the luteal phase, does not affect appetite. Although he, as “the pregnancy hormone” was supposed to be the appetite to amplify it. But – “idles” progesterone.
The mechanism of appetite suppression by estrogens has not yet been clarified. Yes-imagine! Some readers may wonder – is it possible to speak of any action without knowing its mechanism? And the most strict and categorical say – all this bullshit, idle inventions! Mechanism of action there!
You can! You can talk about action without knowing its mechanism! The fact is that discoveries are often made in experiments with a completely different purpose.
Here’s an example, conditional, but indicative.
Scientists studied the comparative effect of diets with a predominance of proteins and carbohydrates on the body of orangutans. Took three groups of animals, one was given a balanced diet, that is, ordinary natural, the diet was dominated by another protein food is bird eggs, insects, and the third diet was a pronounced “bias” towards carbohydrate foods. And suddenly the scientists noticed that the appetite in males throughout the experience remained about the same, and females were subject to severe periodic fluctuations.
Scientists became interested, began to think. It was decided that it was the hormones whose concentration in the blood changes during the menstrual-ovarian cycle (for females orangutan is characterized by menstrual-ovarian cycle, not heat , as in most mammals, and the duration of the cycle they are about the same as in humans – an average of 28 days). Appetite increased after ovulation and decreased with the onset of menstruation. It was necessary to determine the “culprit”, that is, the hormone that affects the appetite. Not suppress appetite estrogen, not the progesterone it stimulates.
To search for the “culprit” was delivered to the rats. Again took three groups of animals, only females. One of them had nothing to do with it, it was a so-called “control group”, kept in exactly the same conditions and received exactly the same diet as the other two groups. For some time, all three groups were simply observed, recording the basic physiological parameters (temperature, heart rate and pulse rate). The second group of rats then had their ovaries removed to dramatically reduce estrogen production in the body. But rats from the third group, on the contrary, began to make regular injections of estrogen. Subsequent observations showed that in rats from the second group after surgery appetite increased dramatically, and in rats from the third group after the start of estrogen administration – sharply decreased. Thus, it was suggested about the depressing effect of estrogen on appetite, which was confirmed by numerous subsequent studies, including with the participation of people (do not worry, if people participate in the experiments, such methods as forced removal of organs are never used).
The large number of confirmations obtained in the course of research makes the assumption a recognized fact. The mechanism may remain unclear, but the fact that estrogens reduce appetite, proven one hundred percent. And this knowledge can be used for scientific and therapeutic purposes. Just like this.
As for the mechanism of action, the most common (and therefore the most recognized, although unconfirmed) version is the version of the stimulation of estrogen ventromedial nuclei of the hypothalamus…
Now we have come to the point where we should have started this Chapter.
So it would have happened if not for Schiller and his love. However, we started with Schiller not just like that, but with meaning. But the meaning will be said…
The hypothalamus is the Supreme Commander of all hormone-dependent processes in the body, including food behavior.
The nerve cells of the hypothalamus, performing similar functions and arranged in groups, are called “nuclei”. In total, the hypothalamus distinguish more than 30 nuclei, most of which are paired. Pair of nuclei called the ventromedial (let’s not going to delve into why they were named so in order not to complicate the presentation of the material), responsible for the appetite suppression, that is, are the “satiety center”. When they stimulate the appetite decreases and their destruction increases. Another pair of nuclei-lateral or “center of hunger”, increases appetite. Well, you understand that without balance, that is-without two competing groups of nerve cells, no regulation is possible. The” food ” balance of the hypothalamus is based on the fact that with a sufficient amount of energy (nutrients), ventromedial nuclei dominate, suppressing the activity of the lateral divisions, and with a lack of energy, the lateral nuclei take over.
Estrogens stimulate the ventromedial nucleus of the hypothalamus, thereby reducing appetite. This is the main version.
Now let’s think – why estrogens are so inconsistent? Why do they show such “voluntarism”?
Pause and think. But don’t try to guess by pointing at the sky (or the ceiling). The explanation is logical, as everything arranged by nature is logical. It is necessary to think, not to guess.
If you haven’t guessed, here’s a hint – reread the passage from Schiller given at the beginning of this Chapter. Readers who know German and to read Schiller’s “Die Weltweisen” in the original, should take as a hint it is the translation of Lev Ginsburg in which love comes first. In the original, the practical Schiller’s hunger is first. Here are the four concluding lines of the poem:
“Einstweilen bis den Bau der Welt
Philosophie zusammenhä LT,
Erhält sie das Getriebe
Durch Hunger und durch Liebe”.
Love! Love! LOVE!
It’s all about love!
One of the main tasks of sex hormones is to form a sexual desire that leads to sexual intercourse, and to ensure the passage of this process at the proper, qualitative level. In order that hunger does not distract from love, that is, in order that hunger does not suppress sexual desire, it is necessary to suppress the very feeling of hunger. For a while. Until the end of sexual intercourse. After you how to eat to restore energy.
So much for expediency. No voluntarism, only logic and calculation.
Let’s take a little digression from the food topic, since we’re talking about sex and estrogen. There is a persistent (and very pleasant) myth about the incredible rejuvenating effect that sex has on women-the skin becomes more elastic, wrinkles disappear, hair ceases to split… and so on. Men, according to this myth, sex has a rejuvenating effect, but whether has it to a lesser extent, whether men are less inclined to believe in fairy tales.
Yes-in fairy tales!
In fact, there is no direct relationship between the frequency of sex and appearance (skin condition, etc.)!
“But indirect-that is!”–thought now, many of our readers, caught the eye of the word “direct”.
And indirect no. The point is that cause and effect should not be confused. Women (and men too) with normal function of the sexual glands in the body produces a normal amount of sex hormones. As a result, they tend to have sex more often and look better than those who do not have enough sex hormones. So do not expect to rejuvenate with sex and forgive the author for what he disappointed you.
And how do testosterone and other androgens affect appetite?
Yes, just like estrogens-oppress it in the interests of sexual desire, so as not to interfere with people to have sex and reproduce. Procreation is the main physiological goal of any organism, which is actually more important than the instinct of self-preservation. Don’t you agree? Yes can you remember any example from the biography of people you know who risked life for love (obviously such examples exist), or take the example of fatal love Bogomolov ordinary, arthropods insects. One of the most famous features of the common mantis is the females, which devour the males after, and sometimes even during mating, as they experience during this period a high need for protein necessary for them to develop eggs and lay them in a protective protein capsule.
Do you think that the male does not feel emanating from females threats? Scarcely. Probably feels it. And even more so feels that the partner begins to gradually eat his brain. Contrary to popular belief, the female mantis does not bite off the male’s head at once. To do this, it is too small mouth, it is not the lion. During copulation, holding the male with front paws, the female begins to eat his head, which the male simply can not feel. However, the instinct of reproduction prevails over the instinct of self-preservation. Selflessly performing his duty, the male meekly allows his partner to feast on his head. Almost self the head in the mouth of vanities. After mating, the female calmly eats everything else.
Anabolic steroids, synthetic analogues of testosterone, also stimulate appetite, and most of them do it even stronger than testosterone.
Inquisitive and thoughtful readers may now wonder – why people who are obese, do not suffer at the same time and poor appetite? On the contrary – their appetite is the best. Why? After all, adipose tissue produces estrogens, which are supposed to suppress the appetite. And the more fat accumulates, the more estrogen should be produced…
That’s true, but there are three things to consider.
First, in adipose tissue is produced” weak ” estrogen, not the great and mighty estrogen.
Secondly, sex hormones take part in the formation of eating behavior together with other hormones. And with other hormones can be different options.
And, thirdly, overeating, leading to obesity, has not only a physiological component, but also a psychological one. And quite often psychology dominates the physiology, that is, a person eats not in order to supply the body with energy, but for the sake of pleasant taste sensations. This topic we will not develop further, because it is very deep and can take us far away from our friends hormones. But the couple of words you need to say.
When controlling the amount of food consumed taste plays a leading role. We usually eat more tasty than tasteless, because we do not so much like to satisfy hunger, as the process of obtaining pleasant sensations. So, in the course of experiments on animals, and specifically-on rats, there was evidence that estradiol reduces the need to enjoy the taste, that is-equalizes the amount and speed of eating delicious and tasteless food. In the case of rats, sucrose – cane or beet sugar-served as a delicious meal. After removing the ovaries, the rats ate sugar without much enthusiasm, at the same rate as other, “normal” food.
Very interesting effect on feeding behavior norepinephrine. And so, and so – and our, and your. On the one hand, acting on the receptors of nerve cells in the brain, norepinephrine inhibits hunger. On the other hand, acting on the receptors of fat cells, stimulates the production of fat, which occurs with the absorption of energy, that is, indirectly stimulates appetite. But if you add up both opposite actions, it turns out that in General norepinephrine oppresses the feeling of hunger. Directly at the peak of furious anger about food somehow do not think, right? Hungry after, when it begins to “let go”.
Increases appetite somatoliberin, a hypothalamus hormone that stimulates the production of growth hormone somatotropin in the pituitary gland. Differently, the border of which simply can’t behave, not allowed. If you promote the growth of the body, if you stimulate metabolic processes (through somatotropin), then be kind to provide an appropriate appetite. As they say: “you love to ride down the mountain, love and sledge up the hill to carry.”
Cortisol, like all glucocorticoids (remember that this is the name of all steroid hormones produced in the cortical layer of the adrenal glands), stimulates appetite. Again, you can remember about the sled, because glucocorticoids do the following:
- increase the production of glucose from amino acids in the liver (and amino acids should be obtained with food, is not it?);
- increase the production of glycogen in the liver and skeletal muscles (and to create reserves you need to have an influx of energy and substrates from the outside);
- stimulate the production of fats.
How not to stimulate the appetite? No way! The body will not understand such negligence.
It cortisol is a hormonal cause “galling stress”, the reason for intensive feeding on the background of different experiences. In addition to hormonal, there is also a reason of psychological nature-the desire to please yourself (cabbage and carrots stress is usually not eaten, choose chocolate and other sweets), but we will not touch it.
Which suppresses appetite norepinephrine under stress abruptly released into the blood very soon inactivated. The same thing happens with adrenaline. Norepinephrine and adrenaline can be called” fast-acting ” stress hormones. Cortisol also inactivated much slower to develop it after the stress decreases too slowly, so it exerts its appetite stimulant effect much longer. And increase cortisol production “starts”, i.e. stimulated, it is much easier than increasing production of adrenaline and noradrenaline.
Unfairly so, if you think about it – reduce appetite norepinephrine is “thrown” into the blood only if a strong body tension, and cortisol slowly “slipped” into the blood when the memories of the incident and other painful thoughts. And the heart is no longer “part”, and breathing evened out, and the fever drops, and cortisol continues to be produced to the fulfillment of the physiological plan… the Man himself does not notice, how will eat a pound of chocolates and four cakes into the bargain. And then, feeling that the oppressive thoughts added oppressive heaviness in the stomach, will reproach himself-Oh, I’m sorry, I should have restrained myself. But to blame a nasty insidious cortisol. That’s it.
Doctors jokingly say that the main “food” hormone is glucose. In fact-so it is, because the feelings of satiety and hunger depend on the concentration of glucose in the blood. High concentration of glucose suppresses appetite, causes a feeling of saturation, and low causes hunger. This property of glucose can be used to control appetite. If you need to reduce appetite, you can eat before eating the piece of sugar (the key word is “piece”!). Taken inside sucrose almost instantly disintegrate into glucose and fructose, which are just as quickly absorbed into the blood and “deceive” the body, reduce appetite.
But, firstly, glucose is not a hormone (explain yourself why it is not a hormone), and, secondly, the feeling of saturation is a complex, or more precisely, a complex feeling. If it was regulated only by the content of nutrients-glucose and amino acids (Yes, and amino acids are also involved in the regulation process on a par with glucose), then we would be incredibly overeated. Once we started eating, we would continue to do so until digested food would cover the energy needs of the body. But the digestion of food is a long, many hours…
On the one hand, where will everything fit if you eat continuously for at least four hours while the food is digested?
On the other – who likes to be tormented by hours of hunger every day, if you stop eating long before saturation?
Fortunately, nature “hedged” with the help of special receptors located in the oral cavity, pharynx, esophagus and stomach. Stimulation of these receptors by chewing and swallowing, as well as by stretching the stomach by food masses, contributes (and quite a significant contribution!) in the noble cause of the struggle against hunger, in the formation of a sense of satiety. The psychological component also plays a role – the very sight of a plate of food sends a signal to the brain: “Everything is fine! There is food, now I will satisfy my hunger.”
High concentration of glucose in the blood suppresses appetite. Therefore, if the hormone of the pancreas insulin promotes the absorption of glucose by the cells of the body (that is, it reduces the level of glucose in the blood), it thus indirectly stimulates appetite. Accordingly, another hormone of the pancreas – glucagon, which increases the level of glucose in the blood, stimulating the breakdown of glycogen and glucose synthesis from other substances, indirectly inhibits appetite. Another balance in the multi-stage balanced life of the body.
Actually, if you draw on a large sheet of paper of the person, labeling all his organs, and next to write in a column all produce the hormones and begin to draw lines linking hormones with the organ in which they are produced or which they act, we’ll get such “web”, which without a pint of tea not understand. Jokes are jokes, but keep in mind that this exercise helps to better absorb the material.
And now let’s talk about the most intimate and secret, about what until recently was hidden from us behind seven locks, and even covered with seven blankets…
Are you intrigued? Curiosity has been rekindled-I’ve worked?
The hormones with which we are now going to get acquainted deserve increased curiosity, that is, increased attention, because one of them is the “main” hormone of saturation, and the other – the “main” hormone of hunger. (The word “chief” indicates the main” specialty ” of the hormone.)
What does the seven castles and seven veils?
And despite the fact that these hormones were discovered at the end of the last century.
We start with the hunger hormone ghrelin, despite the fact that it is five years younger than the saturation hormone leptin. Leptin was opened in 1994 and ghrelin in 1999. But hunger is primary, and the saturation of the second time – first was hunger, and then stopped it, so ghrelin is the first number.
Ghrelin is a substance of protein nature which is produced in many organs – lungs, pancreas, kidneys, small intestine, in the gonads, the placenta, and also in the hypothalamus.
In addition to its main “specialty”, grelin has several additional, however, all of them to some extent relate to eating behavior.
Ghrelin stimulates the production of somatotropin in the pituitary gland, and somatotropin, as you already know, increases appetite, that is, helps ghrelin in this matter.
Ghrelin stimulates the accumulation of energy reserves in the form of fat and glycogen.
Ghrelin improves cognitive activity processes that help to adapt to changing environmental conditions. You may ask-what could be the connection with eating behavior? Very simple – the process of finding food is a process of cognitive activity (search as such), occurring in the environment, under constantly changing conditions. Here is a simple example. You’re a tourist. During a walk through an unfamiliar city, you felt hungry and began to look for where it can be quenched. You make an assessment of the environment, choosing the most promising and convenient for you search direction. Moving in this direction, you continue to assess the changing conditions (change one location to another) as long as you do not find a suitable place for you. This is the search for food in the environment, under constantly changing conditions. It is not necessary to run with a gun in the woods and meadows.
And ghrelin inhibits the production of insulin in the pancreas, acting as an antagonist of glucose, this production is stimulating. It is here that ghrelin “contradicts himself”, because insulin indirectly stimulates appetite. Why do you think this is happening? Why relinu to oppress elaboration of their “ally” of insulin?
The fact is that ghrelin is a hunger hormone, and during hunger insulin in large quantities is not needed by the body. The main purpose of insulin-to promote the absorption of glucose cells of the body. If there is no glucose in the blood yet, then why do you need insulin? His time will come when the process of digestion of eaten food begins. But this is still far away…
Let’s see how our hunger hormone does its main job.
First, ghrelin stimulates the production in the hypothalamus of the so – called neuropeptide Y, which is a powerful stimulant of food activity, that is, encourages us to find food and eat it (the word “neuropeptide” is translated as “a substance of protein nature, that is-consisting of amino acids, produced by the cells of the nervous system). Neuropeptide Y acts directly on the hypothalamic centers of saturation and hunger. And along the way, it has the ability to suppress sexual function, similar to how sex hormones suppress hunger. There’s no need to be distracted by trifles, first you need to eat properly!
Secondly, ghrelin stimulates the production of dopamine in the brain, and dopamine as a neurotransmitter causes not only a sense of pleasure or satisfaction, but also the desire to get this pleasure. Previously, we did not talk about this property of dopamine, we saved the information for the current Chapter, so to speak – to the place. Dopamine ghrelin “increases” the stimulation of feeding activity caused by neuropeptide Y. Tandem “ghrelin – neuropeptide” acts to suppress all other feelings, and with a high degree of expressiveness – even self-control. No wonder people say: “Hunger is not an aunt-does not tolerate” or “Hunger and drives the wolf out of the forest.”
All of the above functions ghrelin is able to perform only after activation by attaching to its molecule octanic acid. This acid is very interesting (many will say – cool) chemical structural formula similar to the two-headed snake.
The addition of octanic acid to ghrelin occurs in the stomach and pancreas, using the enzyme ghrelin O-acyltransferase.
Many readers may wonder-why do we need additional activation of hormones? Why complicate? Isn’t it easier to immediately produce a hormone that is completely ready for action? It’s better…
Easier, Yes. But no better. Additional actions, such as activation, increase the body’s resistance to various and completely unnecessary changes.
For example, the result of exposure to some external factor, for example (conventionally!)- ultraviolet radiation, sharply increases the production of ghrelin in the body. More than enough is as bad as less. Large amounts of ghrelin will provoke overeating. But the body has a buffer-the activation system. With this buffer can be activated only physiologically required amount of hormone. However, it may happen that the buffer will also fail, but the probability of this is less.
The discovery of ghrelin played a very important role in the treatment of obesity, allowed to explain why some people have a “heroic appetite”, which previously doctors could not explain any reasons other than psychological. It turned out that the blame is not the habit of gluttony as such, and increased production of ghrelin in the body. Scientists are actively developing an anti-obesity vaccine that can cause the body to produce its own antibodies against ghrelin, that is, to destroy the hunger hormone, preventing it from stimulating the production of neuropeptide Y. They’re getting somewhere, there are encouraging achievements, but the experiments on rats have not yet progressed.
With age, the production of ghrelin increases. This increase is compensatory in nature, because as you age the function of the digestive system fades, which can lead to a complete loss of appetite. To prevent this, the body produces more ghrelin. But, as you know, any medal has two sides. “Shock” production of ghrelin may contribute to obesity in the elderly.
At the end of the acquaintance it is necessary to mention one more function of ghrelin, which has nothing to do with eating behavior. This function is an example of the prudent device of our body, in which, according to the idea of mother nature, nothing should be superfluous, to be “out of work”.
In the body of the fetus, ghrelin is also produced. In the lungs. And works “at the place of production”, contributing to the development of this body and the entire respiratory system as a whole. The fetus does not take food on its own, it gets everything it needs from the mother, so it does not need to feel hungry. But the hormone-hard worker is not allowed to sit idle, so he is engaged in the development of the respiratory system of the fetus.
With the hormone of hunger gelina we finished, moving on to leptin, the hormone of satiety, suppressing appetite.
Like ghrelin, leptin is a substance of protein nature, only it is produced not by nerve cells, but by fat cells. Production of leptin – another example of the internal balance of our body, arranged on the principle of feedback. The more fat cells (that is, in fact-the more fat), the more leptin is produced in the body, the stronger appetite is suppressed. Fat deposits send a signal to the brain (specifically the hypothalamus): “Stop! Stop eating! Energy reserves deferred good!»
If you are somewhere in popular or medical literature to meet the mysterious word “adipokines”, you should know that these are hormones produced by fat cells, which are scientifically called “adipocytes”. Leptin is one of the adipokines and the only one who was “lucky” to get into this book. We review not all the hormones in a row, and only the most important.
Can you guess exactly how leptin lowers appetite?
Of course, by suppressing the production of neuropeptide Y and releasing it into the blood! That is, leptin is the antagonist of ghrelin, its direct opposite.
Leptin is a signal not only for the hypothalamus, but also for the ovaries. Through the production of leptin, adipose tissue makes it clear to the ovaries that there are enough reserves, it’s time to think about the offspring, that is, it’s time to begin to perform reproductive function. Simply put-leptin stimulates the production of estrogen in the body of women. It is leptin “to blame” for the cessation of ovulation and menstruation with severe exhaustion. A marked decrease in the concentration of leptin in the blood “turns off” the ovaries, stops the production of estrogens.
And leptin has the ability to increase the sensitivity of liver and muscle cells to the action of insulin, which is generally good and useful. But the excess of leptin in the body can lead to the suppression of insulin production, blocking the action of insulin on the liver cells, and the development of General immunity to insulin, which is very bad. Leptin is one of the factors leading to the development of type II diabetes or insulin-dependent diabetes mellitus, in which the sensitivity of cells to insulin is primarily impaired.
In studies involving obese people, such a “paradox” has been observed as a consistently high content of leptin in the blood. At first glance, this can not be, because leptin does not contribute to weight gain, and its reduction. But if you think about it, it is easy to guess that obesity is impaired susceptibility of the hypothalamus to leptin, disrupted the normal operation of leptin receptors. Confirmation of such a guess (and yet it’s just a guess, nothing more) is the lack of effect of injections of leptin in the vast majority of obese patients. Only with insufficient production of leptin while maintaining the sensitivity of receptors to it, injections give an effect.
Receptors sensitive to leptin, there are platelets, shaped elements of blood involved in the process of coagulation. The connection of leptin molecules with these receptors promotes platelet bonding, that is, the formation of blood clots. For unknown reasons, which otherwise than the action of the universal law of meanness can not be explained, platelet receptors do not lose sensitivity to leptin in obesity. As a result, high levels of leptin in the blood increase the risk of blood vessel blockage by blood clots, which leads to serious diseases such as heart attacks and strokes. Not only does leptin not benefit obesity, but it can also cause harm!
Many people occasionally or regularly visit the desire to eat something at night. Some feel this feeling during the night vigils, and others simply wakes up and sends to the refrigerator. Do not rush to write off all the bad habits! Habits have nothing to do with it. The culprit of night “gluttony” is the hormone of the epiphysis melatonin, regulator of circadian rhythms and a number of other processes. Melatonin tends to inhibit the production of leptin, and since the “peak” production of melatonin falls on the night time, at this time the most heavily inhibited production of leptin.
The question arises – why do we need such a “gift” as a night-time reduction in the production of the hormone saturation? That’s unreasonable. On the contrary, at night, during sleep, it is necessary to increase in every possible way the production of the hormone of saturation and suppress the production of the hormone of hunger, so that sleep was strong and would not want to make night sorties to the refrigerator. Again – on a full stomach sleep worse, it is scientifically proven fact. But the fact that from late – night or night food in the body deposited more fat than from the morning or afternoon-a myth. In the body there is a single mechanism of fat synthesis, which in no way depends on the time of eating.
So what is it?
And the fact is that during sleep, the body recovers strength and nature has arranged so that in the morning after waking up, our recovered body experienced hunger, prompting him to look for food. Agree, that with fresh forces seek food easier and more effectively, is true? At the time when this mechanism was laid, refrigerators and supermarkets did not exist, food had to be sought and extracted in the full sense of these words. And to be always on the lookout, to be ready to fight, or to flee, so as not to become one’s own food.
Progress has greatly improved and facilitated our lives, but at the same time it” turned inside out ” many reasonable mechanisms inherent in us by nature. “Twisted” in the sense that now they seem unreasonable to us, although in fact it is not.
The hypothalamus is the Supreme Control Center for all hormone-dependent processes in the body, including eating behavior.
In our body produces the hunger hormone ghrelin and the satiety hormone leptin. They both have a protein nature and exert their effects by stimulating (ghrelin) and oppression (leptin) production in the hypothalamus neuropeptide Y. This neuropeptide is a potent stimulator of feeding activity.
Ghrelin is produced in many organs – lungs, pancreas, kidneys, small intestine, in the gonads, the placenta, and also in the hypothalamus. Leptin is produced by fat cells.
Estrogens have the ability to suppress appetite and therefore in the follicular phase of the menstrual-ovarian cycle, which begins on the first day of menstruation and lasts until ovulation, women of reproductive age experience less appetite than in the luteal phase, which begins after ovulation. One of the main tasks of estrogens as sex hormones is to form a sexual desire that leads to sexual intercourse and ensure the passage of this process at the proper level. In order that hunger does not distract from love, that is, in order that hunger does not suppress sexual desire, it is necessary to suppress the very feeling of hunger (and the hunger hormone ghrelin, in turn, suppresses sexual desire by reducing the production of estrogens, so that no other urges do not distract the body from finding food and eating it).
Noradrenaline, on the one hand, acting on the receptors of nerve cells of the brain, suppresses hunger, and on the other, acting on the receptors of fat cells, stimulates the production of fat, which occurs with the absorption of energy, that is, indirectly stimulates appetite. But if you add up both opposite actions, it turns out that in General noradrenaline hunger depresses.
Increases appetite somatoliberin, a hypothalamus hormone that stimulates the production of growth hormone somatotropin in the pituitary gland.
Cortisol, like all glucocorticoids, stimulates appetite. It cortisol is a hormonal cause “galling stress”, the reason for intensive feeding on the background of different experiences. Which suppresses appetite norepinephrine under stress abruptly released into the blood very soon inactivated. Cortisol also inactivated much slower to develop it after the stress decreases too slowly, so it exerts its appetite stimulant effect much longer. And increase cortisol production “starts”, i.e. stimulated, it is much easier than increasing production of adrenaline and noradrenaline.
Doctors jokingly say that the main “food” hormone is glucose. In fact-so it is, because the feelings of satiety and hunger depend on the concentration of glucose in the blood. High concentration of glucose suppresses appetite, causes a feeling of saturation, and low causes hunger.