This Chapter is better not to read at night, because it is very scary.
A joke and nothing but a joke.
Read whenever you want, and don’t be afraid of killer hormones.
Can our useful little helpers-hormones to be killers?
“Hardly!”,- you will say.
“Genius and villainy are two incompatible things,” said the poet, and this is clear as a simple scale.
And in General we have in the body “regular killers” or, if you want, “regular guards with a license to kill” – the cells of the immune system, whose duties include the decisive and merciless destruction of harmful microorganisms, insidiously penetrating into our body in all sorts of ways. At the same time, these cells deal with internal enemies – atypical cells that can cause cancer.
About the effect of hormones on the immune system, we have already talked and will not repeat. But it should be borne in mind that the immune system fights the enemies of the body. Figuratively speaking-with those who are fighting with weapons in their hands, who in case of victory is able to cause harm to the body.
But there are cells in the body that are not enemies and can not cause harm, but simply “outlived their”, fulfilled their purpose and are to be replaced with new cells. Remember the self-renewal of the body, the essence of which is that the old cells are gradually replaced by new ones. The life span of each type of cell is different, but if we deduce the arithmetic mean, we can say that for a period of seven to ten years there is almost complete renewal of the body. We are updated, but we do not notice it.
There is a question, not on our topic, but very important-why in this case, with the constant renewal of the human body does not live forever?
The exact answer to this question is not yet available. Scientists disagree. If we try to generalize the currently available theories of aging, we can say this: not that death is inherent in the genes, not that it is caused by free radicals-particles containing one or more unpaired electrons on the outer electron shell and, consequently, extremely active in chemical reactions. If you want to delve deeper into the topic, then type in the search engine “theory of aging” and a few hours of fascinating reading you will be provided. And we will return to what the body needs to do with obsolete cells.
No, you just imagine-if a complete (well – almost complete) renewal of the body occurs every ten years (take the maximum period), then what is the intensity! At the cellular level!
Of course, obsolete cells must be destroyed. But they can not be destroyed by the cells of the immune system, because they are their own, and the immune system is directed only against aliens, alien agents. If you aim the immune system at its own cells of the body, it will begin to “eat” them all indiscriminately, that is, without regard to whether they have outlived their age or not. This is what happens in autoimmune diseases, when the immune system from a weapon of defense turns into a weapon of destruction.
The death of its own cells in the body can occur in two ways-in the form of necrosis and apoptosis.
Necrosis is a painful death that occurred as a result of damage (burn, compression, defeat by microorganisms, etc.).
Apoptosis is a natural” programmed ” death, the name of which comes from the Greek word “apoptosis” – leaf fall. Poetic name, isn’t it? And the essence of the process reflects correctly, because apoptosis is as natural as leaf fall.
The term “apoptosis “is very” young”, it is not yet half a century old, which from the point of view of science – just infancy. It was first described in 1972 as a special form of cell death distinct from necrosis.
Necrosis is a passive process that takes place under the influence of a damaging agent. Apoptosis is an active process of self-destruction of the cell, occurring by a genetically programmed mechanism. Apoptosis consists of many reactions that are controlled…
Well, of course, hormones – “killer hormones”! Where without them in such an important matter.
Apoptosis begins in the prenatal period and continues throughout the life of the body. Yes-in the womb, when everything is just beginning and, it would seem, there is nothing to destroy. But in fact, the “rudimentary” cells from which organs subsequently develop are subject to destruction after they have fulfilled their function.
Let’s look at the process of apoptosis in detail.
The process of apoptosis is triggered when there is such damage to the DNA stored in the cell nucleus, which can not be corrected by the cell’s own forces.
DNA is a program of cell activity that determines everything that happens in the cell, including apoptosis, the final stage of cellular life.
If the cell “strayed from the collective”, that is, lost contact with the intercellular substance or neighboring cells (for example – got from the organ into the blood), it is also subjected to apoptosis. In tumor cells, apoptosis is suppressed or absent at all, so they can migrate through the body with blood and form huge tumors.
Sometimes apoptosis is activated by viruses as a” black ingratitude ” to the cell for using its resources. Once inside the cell, the virus replicates itself in it, taking advantage of everything it needs, and then triggers the mechanism of self-destruction of the obsolete cell. But viruses can also suppress apoptosis to multiply in a cell.
At the very beginning of apoptosis, the cell decreases in size, its cytoplasm condenses (thickens), as the water comes out, the process of destruction of proteins by the cell’s own enzymes starts. Then there is a splitting of DNA molecules into a large number of fragments, as a result, the nucleus of the cell (the place of storage of DNA) breaks down into several parts. The cytoplasm is compacted more and more, the cell membrane vpyachivaetsya inside the cell “wrinkled”.
The destruction is in full swing, at some point the cell breaks up into fragments called “apoptotic corpuscles”, which are absorbed by the surrounding healthy cells.
In necrosis, the cell does not shrink, but swells and bursts. Intracellular content islevsel out, causing inflammation.
Note-in necrosis, the cell decomposes, and the harmful end products of this decomposition are removed from the body, providing “along the way” damaging (inflammation) and toxic effect on the body. In apoptosis, nothing harmful to the body is not formed, the intracellular contents are not poured out, because all the fragments into which the cell breaks down in apoptosis are surrounded by a membrane. The dead cell becomes” food ” for neighbors, such here is physiological cellular cannibalism.
Apoptosis is very important for the body. About the fact that it is an obstacle to the development of tumor processes, has already been said. But this is only one facet.
Apoptosis ensures proper fetal development. Violation of apoptosis in the prenatal period leads to the appearance of various anomalies…
Apoptosis maintains the constancy of the cellular composition in tissues…
Apoptosis provides rejection of the endometrium during the menstrual cycle and reduction of the mammary glands after the cessation of lactation…
However, all the processes in which apoptosis plays a role, it makes no sense to list, it’s too long. An idea of the scale of apoptosis can be created with the help of a single figure – in the adult body as a result of apoptosis every day destroyed about 60 000 000 000 cells. Sixty billion a day! Almost seven hundred thousand a second!
Apoptosis is regulated by a number of factors, including hormones, the role of which we will talk in more detail.
An interesting feature – nonspecific factors that stimulate apoptosis (temperature, free radicals, etc.) with increasing its impact, that is, with an increase in the dose of the agent received by the body, lead to the development of necrosis. In small doses cause apoptosis, in large-necrosis, such here is “cunning.” Hormones also do not cause necrosis, change of their amounts may cause a greater stimulation or greater inhibition of apoptosis, but in any case not necrosis.
With hormonal regulation of apoptosis doctors faced before this phenomenon was discovered and studied.
It all started with surgery. It has been observed that surgical removal of the endocrine gland leads to mass involution of target organs. Involution (in Latin – “clotting”) is a reverse development agencies, simplifying their structure and reducing their functions. An example is the involution of the uterus after childbirth or, say, atrophy of an organ in the process of natural aging.
In the old days, knowledge of endocrinology was accumulated a little, but the fact that the testicles control sexual function, mankind discovered in ancient times. Castration, according to historians, is one of the earliest surgical operations. So, in the nineteenth century, doctors who conducted autopsies of corpses, found that all men who have undergone castration during life, the prostate gland eventually atrophies, decreases. This decrease is literally evident, because all other men prostate increases with age. It was concluded that the testicles somehow cause the growth of prostate tissue or prevent its involution. It was easy to guess that it was some substances secreted by the testicles into the blood, because it was the blood that connected the testicles with the prostate gland.
The great detective Sherlock Holmes argued that those who know how to ask the right questions get the right answers. Over time, it was found that androgens inhibit apoptosis of prostate cells. But for the apoptosis of follicular cells of the ovaries the same androgens stimulate. Logical? Logically, male sex hormones should create favorable conditions for the growth of male organs and unfavorable – for women (the words “favorable” and “unfavorable” are used for fun and do not reflect the real situation).
Hormones can have different effects not only on apoptosis of different cells, but on apoptosis of the same cells depending on their age (stage of cell development). For example, estrogens inhibit the apoptosis of the cells of the uterine mucosa at the beginning of the menstrual cycle and stimulate it at the end of the cycle, when there is a rejection of cells. And progesterone, as a pregnancy hormone, suppresses the apoptosis of the cells of the uterine mucosa at the end of the cycle.
You haven’t forgotten about the osteoclasts – the cells-the destroyers of bone tissue? Estrogens not only inhibit the development and activity of osteoclasts, but also stimulate their apoptosis.
“There was a man, and the article for him there” – joking of experienced investigators and detectives. About the same can be said about hormones. Most of them can be accused of murder-in the stimulation of apoptosis of certain cells of our body.
The main side effect of combined oral contraceptives containing estrogens and progestins (synthetic analogues of progesterone) is infertility, which can occur in young women taking oral contraceptives from an early age and for a long time. Why do you think this is happening? Because progestins stimulate apoptosis of epithelial ovarian cells (that is, cells lining the inner surface of the follicle).
Age-related physiological atrophy of the organ-thymus gland, sex glands, bones, muscles, skin, intervertebral cartilage, etc. – is the result of a decrease in the production of hormones that inhibit apoptosis in this organ. The amount of hormone decreased-the cells began to self-destruct in large quantities-that’s you and atrophy.
Accordingly, age-related hyperplasia of the organ is a consequence of a decrease in the production of hormones that stimulate apoptosis in this organ (for example, the action of androgens on the prostate gland).
The study of apoptosis in our time is very important. Think for yourself-why? What can be the practical meaning of stimulation of apoptosis in cells?
Of course-in the treatment of cancer. Figuratively speaking, the first thing an ordinary cell does when it turns into a tumor cell is to get rid of the apoptosis program embedded in its DNA. The cell acquires conditional immortality and begins to “Rob”. With tumor cells trying to fight, killing them with radiation or chemicals, but the body these therapeutic methods also cause great harm. Sometimes even more than tumor cells.
But if you start apoptosis at the “brazen” of tumor cells, and even to stimulate it, then cancer will be considered defeated. Tumor cells self-destruct and instead of poisoning the body with the products of their decay, they become food for the normal “decent” cells surrounding them. Certain types of cancer, such as prostate cancer or breast cancer, are already treated with hormones or competing drugs , stimulating apoptosis of tumor cells.
Regulation of apoptosis can be used not only in cancer. Apoptosis can not only stimulate but also depress, thereby expediting the healing of affected skin burns, heart attacks, etc. there are Great prospects in the application of the regulation of apoptosis in the treatment of blood disorders.
Our body is constantly self-renewing, old cells are gradually replaced by new ones. The life span of each type of cell is different, but if we deduce the arithmetic mean, we can say that for a period of seven to ten years there is almost complete renewal of the body. Obsolete cells must be destroyed. But they can not be destroyed by the cells of the immune system, because they are their own, and the immune system is directed only against foreign agents. Physiological, natural” programmed “death of the body’s own cells is called “apoptosis”. Apoptosis is different from necrosis-a painful death that occurs as a result of damage. When necrosis cell swells and bursts. Intracellular content islevsel out, causing inflammation. In apoptosis, the cell breaks down into membrane-surrounded fragments that are absorbed by surrounding healthy cells. Inflammatory processes in apoptosis do not develop.
In the body of an adult as a result of apoptosis every day destroyed about 60 000 000 000 (sixty billion) cells.
Apoptosis is regulated by a number of factors, including hormones. For example, androgens inhibit prostate cell apoptosis, but stimulate ovarian follicular cell apoptosis. Hormones can have different effects not only on apoptosis of different cells, but on apoptosis of the same cells depending on their age (stage of cell development). Estrogens inhibit the apoptosis of the cells of the lining of the uterus at the beginning of the menstrual cycle and stimulate it at the end of the cycle, when there is a rejection of cells. And progesterone, as a pregnancy hormone, suppresses the apoptosis of the cells of the uterine mucosa at the end of the cycle.
Age-related physiological atrophy of the organ is a consequence of a decrease in the production of hormones that inhibit apoptosis in this organ. Accordingly, age-related hyperplasia of the organ is a consequence of a decrease in the production of hormones that stimulate apoptosis in this organ.