In this Chapter we will talk about hormones-pimps, that is-about hormones that provide mutual attraction of individuals of different sexes and contribute to the sexual intercourse between them was as good as possible. Taking into account the fact that the production of offspring from a biological point of view is the main task of any living organism (if you want, then – the goal of all life), we will understand, realize, feel the importance of “pimps”. Without them, humanity would be extinct as a species.
Yes – would become extinct. From the end. Once and for all. The exact cause of the extinction of the dinosaurs, which disappeared from the face of the Earth about 65 million years ago, is unknown and is unlikely to ever become known, but one version says that it’s all about hormones, not the fall of an asteroid and not a sharp cold snap. Some reasons (solar activity, changes in the magnetic field of our planet, etc.) led to the fact that the ancient lizards stopped breeding, lost all enthusiasm for this cause due to hormonal changes. What? Quite a convincing theory. No worse than an asteroid falling. In any case, it explains why dinosaurs became extinct and mammals that already existed at the time survived.
But let’s leave the mysteries of days gone by and return to hormones.
Here’s a question for you – what is the difference between the relationship between the sexes in humans and animals?
The first clue: the question itself is very complex, but the answer is very simple.
The second clue: think easier, without going into the philosophical wilds. Do not argue that for a person love is a kind of sublime feeling, the psychological component of which… and so on. The question is purely physiological.
Answer: we show or we are able to show interest in individuals of the opposite sex constantly, that is-year-round, and in animals this process is limited to certain time intervals. For example, females to allow themselves to males only during estrus, which happens once or twice a year and lasts about 3-4 weeks. Outside of estrus males are not interested in a bitch, and she does not admit to themselves. And who is “to blame”?
Hormones, of course! By the way, the name “estrogens” comes from the Latin word “estrus” – heat.
We’ll start with estrogen.
The activity of estrogens as female sex hormones can be coded with three letters ” M ” – menarche, menstruation, menopause. Our matchmaking hormones are also mentor hormones, because they prepare the body for the next life period – puberty, childbirth and menopause.
There are three types of estrogens – estradiol, estriol and estrone.
Let’s take another look at their formulas and remember that they refer to steroid hormones because they are steran derivatives.
Biochemists have such a riddle: “what is – four rings, and tails on the side?”Answer: steroids.
All estrogens are formed in the body (both in women and men) from androgens. In the previous Chapter, we have already talked about how in adipose tissue with the participation of the enzyme aromatase testosterone turns into estradiol. The same thing happens with other estrogens. And not only in adipose tissue, but also in the place of the main production – in the ovaries, in the testicles and in the adrenal glands. Androgens are an “intermediate” in estrogen synthesis.
Note that adipose tissue does not produce estrogens “from beginning to end”, but only aromatizes androgens, turning them into estrogens, that is, it carries out only the final stage of the synthesis of estrogens from “semi-finished products” produced in the ovaries and adrenal glands.
By the way, the ability to produce estrogens has only the adipose tissue of humans and some monkeys. No other mammal has fat cells that produce female sex hormones.
Obesity, among other things, increases the production of estrogen. The more adipose tissue, the more products it produces. For this reason, many men who are obese third or fourth degree, look effeminate and suffer from a disorder of potency. Blame estrogen, which are locked in a constant and bitter struggle against their main opponents – androgens. If testosterone stimulates muscle growth, then estradiol will stimulate the accumulation of fat, if testosterone stimulates erection, then estradiol will inhibit it.
The fetus receives estrogens (and other biologically active substances) from the mother and from the placenta. I must say that the fetus does not need such a huge amount of estrogen, which is produced in the body of a pregnant woman.
Judge for yourself – in the mother’s body is such a complex and responsible process as pregnancy, which requires, if I may say so, “a huge hormonal participation”, that is, a large number of hormones, primarily estrogens. But that’s in a pregnant woman’s body. And fruit-what to do with so much estrogen? It is to the fetus not just redundant, and supermediastore. The so-called placental barrier, which regulates the penetration of various substances from the mother’s blood into the fetal blood and back, does not delay estrogens. Although, in theory, would partially limit this penetration, since the estrogen fruit in such amounts is absolutely not necessary. Not useful, but the problems create can.
Clarification – “not needed in such quantities” does not mean “not needed at all.” Sex hormones, both estrogens and androgens, need the fetus, and even as needed. After all, it is under their strict guidance that the formation of the reproductive system in the fetus begins at the end of the second month of intrauterine development. For embryonic development, that is, the period beginning at the moment of fertilization and ends at birth, characterized by a law – every hormone involved in the development of the organs or systems of organs, which he will subsequently be adjusted. Simply put, each hormone provides a workplace, the bridgehead on which it will subsequently act.
But let’s go back to the problems that can create an excess of estrogen in the fetus.
At first glance, this may seem strange – what problems can create such useful hormones?
Yes, at least let’s take as an example too intense stimulation of metabolic processes, as a result of which the fetus will actively grow. Estrogens in varying degrees stimulate a huge number of metabolic processes. If the description of each of these processes is given one page, the result will be a two-volume book. Under the influence of such stimulation, the fetus can become not just large, but heroic.
There are many things that doctors and neurologists disagree about in diametrically opposite ways. For example, neurologists usually rejoice when they learn that someone has a large child: “Hurrah! A real hero! What a big guy!”Doctors are not happy, because they understand how large the size of the fetus complicates childbirth. And doctors know that ” big man “does not mean”healthy.” Newborn “heroes” have much more health problems than their smaller peers.
The fetus has to defend itself. In the fetal liver, estradiol and estrone are converted into estriol, the least biologically active estrogen. All this estriol goes back into the mother’s body, which secretes it in the urine. The mother’s body, even taking into account pregnancy, such amounts of estriol are also not needed, and there is no possibility to process them, so we have to bring them out.
Excess estrogen in newborns (both girls and boys) is manifested in the form of some swelling of the mammary glands and the release of a secret resembling colostrum. Around the seventh day of life, these phenomena disappear, because after the birth of a child, the level of estrogen in his body drops sharply and remains low until about ten years of age, because the sex glands during this period function poorly. If a child is obese, the estrogen in his body will be more than peers with normal weight. But not much more, because in childhood adipose tissue produces estrogens in relatively small quantities.
The pituitary gland produces two gonadotropins or gonadotropins-follicle stimulating hormone and luteinizing hormone. “Gonads “are the sex glands, and” tropos, “as you already know, means”direction.” Gonadotropins are designed to regulate the functioning of the genital glands. The third gonadotropin-chorionic gonadotropin, produced by the placenta, that is present in the body of women only during pregnancy.
From a chemical point of view, gonadotropins are glycoproteins, substances whose molecules are formed by proteins and sugars.
Follicle-stimulating hormone in the ovaries is responsible for maturation of follicles (and thus eggs) and stimulates the production of the enzyme aromatase in the follicles, which, as we know, necessary for the synthesis of estrogen, to be exact – to convert androgens into estrogens.
Luteinizing hormone as well as follicle stimulating, stimulates the maturation of the follicle and the production of estrogen in them. The formulation of estrogen in the follicles from gonadotropin exists a kind of division of labor – the luteinizing hormone stimulates the synthesis of androgens, while FSH is responsible for their flavoring, i.e., for estrogen conversion. As they say, working together is more fun.
Until about the age of ten, gonadotropins are not produced in the pituitary gland. That is, until the age of ten, the sexual glands do not receive “superior stimulation” of the pituitary gland. And the hypothalamus at this time, too, not to the gonads, he’s got other things to do and it does not stimulates the secretion of gonadotropins by GnRH (gonadotropin releasing factor). Not until the sexual glands and the pineal gland, also produce leaks.
Agree that the workflow in the presence of the boss and the workflow in his absence-these are two different workflows. When the boss is away or sick, employees can relax. Here and gonads to ten years, “relax”.
But as soon as the hypothalamus with the epiphysis and the pituitary gland are taken up, the sex glands begin to work intensively, selflessly, as if trying to catch up. In fact, there is nothing “missed”. Everything has its time, in the first years of life the body has some priorities, and then they are replaced by others. In order to properly prepare for such an important matter as reproduction of offspring, the body must reach a certain level in its development. And the more complex the organism is, the longer it “Matures”. Unicellular organisms begin to divide, that is, to multiply in the first hours of their lives, and people need years to reach this threshold, not less than a decade and a half.
The basis of the female sexual system is the ovary – a small paired oval organ located in the pelvis. The ovaries consist of connective tissue, which acts as a supporting structure, and a cortical substance, which contains small globular formations, called “follicles”. Each follicle contains one female sex cell (egg). In addition to the egg, the follicle includes other cells, including those that produce estrogens. The follicles in the ovaries are at different stages of development.
At the time of puberty in each ovary there are several thousand follicles with young, that is-immature, eggs. With the onset of puberty under the influence of estrogens (primarily estradiol) begins the maturation of eggs. In each period of 3-4 weeks Matures one egg. Rarely, but happens so, that simultaneously Mature two eggs or even more. In this case, multiple pregnancies are possible.
The Mature egg goes beyond the ovary and enters the fallopian tube – a muscular tube stretching from the ovary to the uterus. The egg moves along the fallopian tube towards the uterus, but does not go into the uterine cavity, and is delayed in the end part of the tube. If the egg is fertilized by a sperm, then pregnancy occurs – the fertilized egg begins to divide, goes into the uterine cavity and attaches to the wall of the uterus. If the egg is not fertilized, it dies and is replaced by a new one. The essence of the cyclic activity of the female reproductive system, called ” menstrual-ovarian “(or more often, but not quite correctly – “menstrual”) cycle, is the constant development of new eggs instead of unfertilized. During pregnancy, this cycle is temporarily interrupted.
At birth, the ovaries of a newborn girl contain about 300,000 to 400,000 “primary” or “primordial” follicles, which are scientifically called primordial. After birth, new follicles in the ovary are not formed. Moreover, their number is constantly decreasing and reaches 5000-7000 by the age of 18. But they increase in size and undergo changes that can be called “maturation”.
In childhood, before puberty, the development of the sexual system occurs due to the lack of hormonal stimulation. For example, at birth, the uterus, experiencing the influence of maternal estrogens, weighs about 1.8 grams. Then its weight is reduced to 1.3 grams, as the body dramatically reduces the content of estrogen. At the age of ten, the uterus weighs only 2-2. 5 grams, in other words – for ten years it grows about twice. But then the uterus begins to grow intensively and by the age of sixteen increases almost tenfold, weighs 23-25 grams. The reason for this intensification of growth is that the pituitary gland finally “remembers” about the ovaries and makes them produce estrogens. The beginning of estrogen production in the follicles marks the beginning of puberty.
The follicles in the ovaries Mature until the first one bursts, releasing the egg to freedom, more precisely – in the so-called fallopian or fallopian tube connecting the uterine cavity with the abdominal cavity. This moment, the moment of the first period, which occurs in most girls between 11 and 13 years, is called “menarche”, and the output of the egg from the ovary into the fallopian tube is called”ovulation”. With the release of the first egg begins the cyclic activity of the ovaries, manifested in the form of regular menstruation.
Before the onset of menarche (that is, one and a half to two years of ovarian activity) estrogens have time to do a lot. They stimulate the growth of the genital system, provide the formation of secondary sexual characteristics, cause changes in the skeleton (pelvis expands), stimulate the deposition of fat in the pubis and labia majora… (do not forget that the adipose tissue, especially the one that is in the lower half of the body and on the hips, is able to produce estrogens.)
Estrogens also stimulate the growth of the endometrium-the inner lining of the uterus and the development of blood vessels in it. The endometrium can be considered if not the most important, then the most favorite target for estrogens, because it contains a lot of estrogen (estradiol) receptors. Otherwise, it can not be, because the management of the endometrium is a very complex cyclic process. Monthly endometrial cells are prepared to receive fertilized eggs and subsequent care for her. If their hopes are not fulfilled, that is, fertilization and development of pregnancy does not occur, the unfortunate cells die of grief. In fact, of course, not because of grief, but because of its uselessness. Why do you need a pillow if there is no one to sleep on it? Why do we need a layer of cells rich in glands and blood vessels, if it is not destined to turn into a placenta?
You might think that nature would be easier to do only the production of new eggs, instead of unfertilized, without constant replacement of the outer layer of endometrial cells. And how would have been welcome in this case, women who are menstruating deliver a lot of problems (truly – and if not, then bad, and if so, not good). But the fact is that the “outer” cells of the endometrium are programmed for intensive growth, because at the onset of pregnancy, the uterus begins to increase dramatically in size. It is impossible to deprive the cells of this potential, but they have nowhere to develop in the non-pregnant uterus. So the body has to get rid of the old outer layer of endometrial cells and grow a new one to replace it.
By the way, science has not yet discovered a specific hormonal signal for menarche, that conditional “call” after which the first menstrual bleeding begins. This refers to a sharp increase in the production of estrogens or changes in their ratio. Scientists admit that such a signal may not exist at all. Everything happens without a “bell”, of course, when the reproductive system reaches a certain level of development.
The cyclic activity of the ovaries is caused by a cyclic change in the level of estrogen in the blood. During the final maturation of the next follicle, in the so-called follicular phase of the menstrual-ovarian cycle, which begins on the first day of menstruation and lasts until ovulation, estrogen production increases. By the time of ovulation, the estrogen content in the blood reaches its peak.
Note that the change in estrogen production, as well as any other hormones, is a consequence of changes in the production of stimulating hormones of the pituitary gland, and ultimately – changes in the production of liberins and statins in the hypothalamus. But in order not to clutter the text and then unnecessary refinements, we are talking only about the end result of all these metamorphoses, that is, in this case – about estrogens.
Exceptions to this rule will be made only when necessary. So, for example, now needs to be clarified to be clear that at the beginning of the final maturation of the follicle level of the blood content of follicle-stimulating hormone is elevated, and the levels of luteinizing – lowered. During the maturation of the follicle to a state of “full ripeness” the ratio gradually changes in favor of luteinizing hormone, the content of which in the blood at the time of ovulation reaches a peak (similar to estrogen). But the level of follicle stimulating hormone at the time of ovulation is reduced to a minimum. The follicle is stimulated properly, the ripe egg is ready to “go out into the people”, so that the follicle-stimulating hormone can rest a little.
After ovulation, the luteal phase of the menstrual-ovarian cycle or the phase of the yellow body begins. It got its name from the fact that after the release of the egg follicle turns into a yellow body (in Latin it is called “corpus luteum”) – a temporary gland of internal secretion that produces the hormone progesterone, another steroid hormone.