18 October 2016

Hormones, part 1


Atlas, Geektimes

Due to their effect on human mood and behavior, neurotransmitters and their stimulants are very popular. But hormones have not received such fame yet – although they deserve it no less. Atlas decided to rectify the situation and tell how hormones affect each of us – and sometimes in unexpected ways.

First about hormones

Hormones are organic signaling molecules that transmit messages inside the body and are involved in the regulation of internal processes. Hormones are secreted by the endocrine system, enter the bloodstream, move with it in the body, reach and activate target cells and thus control metabolic processes. Hormones are in many ways similar to neurotransmitters, except that they are completely synthesized inside the body and act not only on nerve cells, but also on other tissues.

Hormones are protein, steroid and amino acid derivatives. Protein hormones dissolve well in water, steroid hormones are synthesized from cholesterol and, conversely, avoid water and dissolve in fat. Therefore, they are also called lipid (fat) hormones. To move, steroids need the help of transporter proteins, whereas protein hormones travel independently.

The synthesis of steroid hormones is regulated by the central nervous system. The initial impulse, external or internal, enters the brain. Here the signal is processed and transmitted to the hypothalamus. He begins to produce pathins (stimulating hormones) or statins (inhibitory). They act on the pituitary gland, which in turn gives the command to act to the thyroid and sex glands and adrenal glands, which begin or stop the production of hormones. Synthesized hormones enter the bloodstream and activate processes in tissues and cells.

The hormone reaches the cell it needs and affects its metabolism. Lipid hormones can even interfere with the process of reading genetic information – activate or block the work of some genes. When the task is completed, hormones are broken down in the cell or, a little later, in the liver.

Hormones accompany us for most of our lives – they affect growth, puberty, hunger and satiety, sexual desire, age-related changes. The hormonal system interacts with the immune system, regulates metabolism and affects emotions. In short, it deserves no less attention than neurotransmitters.

Androgen hormones

Androgens are male sex steroid hormones. They are present in both men and women, but they influence the formation of the male constitution. This process begins in the womb – depending on the genes and chromosome set, different types of receptors are activated in the embryo. In boys, they will be sensitive to the mother's testosterone, in girls – to estrogen. Genetically inherent susceptibility to hormones will determine human development.

Studies have shown that men and women differ both on a physiological level and behavioral traits due to biology. Not only external sexual characteristics depend on gender, but also the size of internal organs, the peculiarities of the immune system and the structure of the brain.

Men and women have different sizes of the nuclei of the hypothalamus – the very center of neuroendocrine regulation, which we talked about two paragraphs ago. Women, for example, will have a larger nucleus that regulates the level of luteinizing hormone. It controls the ovulation process in women and testosterone levels in men. The ovulation process is associated with the peak of luteinizing hormone – therefore, this area of the hypothalamus in women is larger.

Due to the high level of testosterone, men will be less prone to anxiety and depression. Women have better verbal memory, and men have better spatial and visual thinking.

Androgens also stimulate metabolism – cell renewal, muscle tissue growth, bone strengthening with calcium and trabeculae (structural components of bone). In addition, they are responsible for more obvious things – the size of the genitals, the growth of beard, mustache and chest hair, a low voice. With a high level of androgens, these signs can also appear in women.

Hormones and their influence on the formation of a person's personality are surrounded by the attention of not only the professional community, which has given rise to many myths. Some studies insist that the mother's testosterone level in the prenatal period affects the development of the fetus, its future behavioral characteristics and even sexual orientation. There is even such an indicator as the ratio of the length of the index and ring finger, which may indicate an increased level of testosterone in the prenatal period and the predominance of "male" behavioral traits in the character, both in men and women. It should be noted here that the main role in the determination and formation of sex is played by genes, which, in turn, will depend on sensitivity to androgens or estrogens.

Androstenedione and androstenediol

Androstenedione is a minor sex hormone that is secreted by the testicles in men, the ovaries in women and, in small amounts, by the adrenal cortex in both sexes. This is a precursor hormone: in the sex glands in men, it is converted into testosterone, in the ovaries and adipose tissue in women - into estrone (female sexual prohormone). If the adipose tissue exceeds the norm, the level of estrogens may also increase in men.

The activity of androstenedione as an androgenic hormone is about 20% of the activity of testosterone, but plays an important role during puberty.

Basically androstenedione is in the blood serum in an inactive state. The concentration of androstenedione increases from the age of seven, but after 30 years it begins to gradually decrease. Androstenedione analysis is prescribed mainly to women for the diagnosis of hyperandrogenism syndrome, a hormonal disorder in which women have excessively pronounced male signs (facial hair grows), and the reproductive system can work poorly. Elevated values of androstenedione indicate features or disorders of steroidogenesis, a reduced level indicates adrenal insufficiency or sickle cell anemia.

Androstenediol is in many ways similar to androstenedione with the difference that it does not precede testosterone, but its active form – dehydrotestosterone. Androstenediol is also synthesized in the adrenal cortex, testicles and ovaries. The increased level is associated with hirsutism and acne in women. Low androstenediol levels in men are associated with hypogonadism – a weakening of the function of the sex glands.

Testosterone and dehydrotestosterone

The main male sex hormone is testosterone, a steroid that is mainly produced in the testicles (testicles), hence its name. It determines the usual androgenic functions – it is responsible for the low timbre of the voice, the growth of hair on the face and chest and hair loss on the head (baldness is associated with high testosterone). In addition, testosterone provides strong bones and muscles, sexual desire, good memory and mood, and what we call "fighting spirit" – energy and readiness for action. In women, testosterone is produced in the adrenal cortex and processed into estrogens in the follicles.

Studies have shown that testosterone can reduce anxiety levels and help to cope with stress. Also, high testosterone levels reduce the risk of depression in men. Therefore, depression is more common in older men (with low testosterone levels) than in younger people. Even in women, depression is accompanied by a reduced level of testosterone compared to normal values. However, in the treatment of depression, androgen replacement therapy has shown the same good results as serotonin reuptake inhibitors.

Testosterone increases significantly during puberty and remains high until the age of 30, then gradually decreases. At the age of 55-60, the so–called "andropause" begins, and from that moment, traditionally, low testosterone is considered the norm - however, modern experts are ready to argue with this. Also, the testosterone level changes throughout the day – it will be as high as possible in the morning after waking up and will decrease to a minimum by the evening.

Within normal values, testosterone levels rise in response to sexual arousal. At the same time, the rise in hormone levels follows the sexual impulse, and does not cause it. However, a sexual stimulus cannot raise testosterone from very low levels: if the hormone level is below normal, no sexual arousal will occur.

With reduced testosterone, all its benefits are gradually canceled: muscles and bones weaken, fatigue appears (especially at the end of the day) and you do not want sex. Attention is dulled and the mood is greatly spoiled – a mature man begins to turn into a grumpy old man. Along with the drop in testosterone, its ability to burn fat also decreases. This and less physical activity lead to the appearance of excess weight and obesity. An overabundance of adipose tissue does not allow the body to produce a sufficient amount of the transporter protein - sex hormone binding globulin (SHBG), which is involved in the transfer of testosterone. In addition, the female hormone estrogen is synthesized in adipose tissue, which promotes the growth of the glandular tissue of the mammary glands.

High doses of testosterone help to build muscle mass and absorb protein from food, so synthetic steroids are a popular means of doping among athletes, especially in heavyweight and bodybuilding. By the way, using synthetic steroids is a bad idea – not only is it illegal, but it is also harmful to health: steroids increase the load on the heart, in high doses have many side effects both from the central nervous system and metabolism, and interfere with normal, endogenous hormone synthesis. In women, steroid hormones form a male physique and disrupt the reproductive system – the athletic benefits of androgens in sports are inseparable from such side effects.

Testosterone itself is not so active, it only precedes the synthesis of dihydrotestosterone. This biologically active formula of testosterone excites the receptors of target cells. Elevated levels of dihydrotestosterone may accompany premature puberty. Critically low hormone levels reduce libido.

Substitution therapy

If the manifestations of low testosterone levels bother the patient, the urologist-andrologist or endocrinologist may prescribe replacement therapy. The reason for this should be a combination of objective signs (for example, a decrease in testosterone levels in the blood) and subjective ones – if the patient is not satisfied with his quality of life, productivity, mood, sexual activity.

Androgen replacement therapy has contraindications and side effects that the doctor should also take into account. Testosterone is contraindicated in people with thrombosis, strokes and heart attacks, as well as gynecomastia and oncological diseases in the anamnesis.

Testosterone is found in the blood serum most often in an inactive state. Therefore, in order to prepare therapy, it is necessary to pass several types of hormone tests. This will be free testosterone – present in the blood, but not bound to proteins; total testosterone – attached to protein transporters; luteinizing hormone (LH) - it stimulates the cells of the sex glands that produce testosterone; and prolactin – elevated levels of this hormone can reduce the level of LH and, as a consequence, androgens.

A decrease in testosterone levels in old age is a normal story, the same "normal" as the life expectancy of 45-50 years. Nature cares about people only for the duration of their reproductive activity – the state of health and the quality of their life after 45 years of age does not care much. But over the past hundred years, life expectancy has increased – and with it, our ideas about when it's time to retire have changed.

Therefore, if you want to keep your body and spirit cheerful, continue doing what you love, or, for example, rule the country, in consultation with your doctor, you can choose hormone therapy and help your body cope with the tasks set by the modern world. Especially for the readers of "Giktimes" consultation with an endocrinologist or urologist-andrologist in the Atlas clinic with a 15% discount. To get a discount, make an appointment for a consultation by phone +7 495 212 0 888 or in a chat on the website and tell me that you learned about the action from Geektimes.

Portal "Eternal youth" http://vechnayamolodost.ru  18.10.2016

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