Estradiol is the primary female sex hormone. Of course, it affects the female reproductive organs and phenomena related to reproduction, but also affects the work of the brain, liver and the condition of bone tissue. The effects of estradiol on the body are so important that preparations containing this hormone play a very important role in medicine.
Estradiol , abbreviated as E2, sometimes also called 17β-estradiol, belongs to estrogens - the main group of female sex hormones next to progestagens. Among estrogens,estradiolis distinguished by the strongest biological activity.
Estradiol: production in the body
Estradiol belongs to the group of steroid hormones - the primary precursor of this hormone is cholesterol. Estradiol is produced through numerous, quite complicated, metabolic changes.
Interestingly, this female sex hormone is derived from androstenedione, a substance considered to be typically male hormone.
In the changes leading to the formation of estradiol from androstenedione - under the influence of the aromatase enzyme - another compound from the estrogen group is formed, which is estrone. This substance, however, reacts with another enzyme, which is 17-beta-hydroxysteroid dehydrogenase, and it is thanks to its action that finally estradiol is produced in the body.
Estradiol answers, among others for the appearance of a typical female body structure, which is related to the fact that it affects the distribution of adipose tissue in the female body.
The changes described above - as you can probably guess - take place mainly in the area of female reproductive organs, and more specifically in the ovaries. The female genitalia, however, are definitely not the only places where estradiol is produced - this hormone is also produced in the adrenal glands (and in people of both sexes). Other tissues in which estradiol or its derivatives are produced are adipose tissue and nervous tissue. In addition to them, estrogen production can also take place within the walls of arterial vessels, and in men, small amounts of estradiol are synthesized in the testes.
Produced in the body, estradiol circulates in the blood in combination with proteins (such as SHBG, or steroid-binding globulinbut it is also attached to albumin). Estradiol combined with a transport protein is inactive - only free estradiol molecules show hormonal activity, the percentage of which, among all estradiol that circulates in the blood, is slightly more than 2%.
Estradiol: functions of estradiol in the female body
Estradiol exerts a huge number of functions in women's bodies - not all of them are, contrary to appearances, related to the activity of the reproductive system. As for purely sexual aspects, estradiol is responsible for the emergence and development of second- and third-order sexual characteristics. It is thanks to him that women experience enlargement of the mammary glands or the development of the vagina and external genitalia - these processes begin with the beginning of sexual maturation, when the female body begins to produce increased amounts of estrogens.
Estradiol and the menstrual cycle
In women who are of childbearing age, the concentration of estradiol in the blood is not constant - it changes during the menstrual cycle. In the course of the first phase of the cycle (in the follicular phase), the concentration of this hormone gradually increases, which is related to the fact that the ovarian follicles produce more and more estradiol. The greatest amounts of estradiol in the female body appear around ovulation - for it to occur, i.e. the release of the egg from the ovary, it is necessary to significantly increase the release of lutropin (LH), and this phenomenon occurs due to the exceptionally elevated estrogen concentration in the body.
After the onset of ovulation, the concentration of estradiol gradually decreases - in the luteal phase it is produced by the corpus luteum, but in much smaller amounts. Ultimately - if fertilization does not take place - the entire cycle of these changes is repeated in the next menstrual cycle.
Estradiol and menopause
There comes a certain stage in the life of every woman, when the amount of estradiol produced in her body drops sharply. We are talking about the onset of menopause, i.e. the last menstruation in a woman's life. Menopause is associated not only with the cessation of monthly bleeding, but also with the fact that patients develop various ailments. They result from the deficiency of estradiol in the body of women and they can be associated with the reduction of bone mass, these ailments can also be, for example, mood disorders - the existence of such possibilities as the above-mentioned possibilities results from the fact that estradiol also affects many others, besides the reproductive system , tissues.
Estradiol adice
Estradiol - along with other estrogen hormones - affects the growth of bones, including the growth of representatives of both sexes. This hormone regulates the closure of the epiphyseal cartilages of bones - when this happens, the growth becomes complete.
Moreover, estradiol has a protective effect on bones - it prevents the resorption of bone tissue. This is why women who reach the menopause (a state where their estradiol levels drop significantly) are at risk of developing both osteopenia and osteoporosis.
Estradiol and the nervous system
In the central nervous system, estradiol corresponds to, inter alia, for stimulating libido, in addition, this hormone also has a thermoregulation-controlling effect. Estradiol - from cholesterol precursors - can also be produced in the nervous tissue. This compound is suspected of having an antioxidant effect, which is why it is treated as a substance that may have neuroprotective effects.
In addition, estradiol influences a woman's mood. Lack of this substance can lead to irritability as well as to depressed mood, sometimes reaching even the level of depression. After all, such problems are associated with the menopause, where there is a significant reduction in the amount of estrogen in patients. It is similar in the case of mood disorders in women who have recently had a baby - during pregnancy, the amount of estradiol in their bodies is increased, but after childbirth they drastically decrease, and this may be the cause of postpartum mood disorders.
Estradiol and the liver
The effect of estradiol on the functioning of the liver is also important. This hormone influences the production of various proteins in this organ (e.g. lipoproteins or proteins related to clotting processes). In large amounts, estradiol, in turn, can lead to cholestasis (bile arrest) - this is the case, for example, in the case of pregnant patients, in whom elevated estradiol levels may lead to the so-called cholestasis of pregnant women.
Worth knowingFunctions of estradiol in the male body
Estradiol is considered a typically female hormone, but it is also needed by men. In the case of men, estrogens are involved in the aforementioned growth processes of the body, but in addition, these hormones are associated with the male reproductive system - in a situation where a man experiences estrogen deficiency, he may experience fertility disorders.
Effect of estradiol on the skin
Estradiol together with other estrogens has a beneficial effect on the skin. Sex hormone receptors have so far been detected, for example, in the skin-building keratinocytes or in fibroblasts. In a situation where the amount of estradiol in the body is reduced, the skin of patients becomes much more prone to wrinkles, much thinner and less hydrated. The relationship between estrogens and the condition of the skin may be convinced by the fact that in patients who use hormone replacement therapy after the menopause, the appearance of their skin may be significantly improved.
Diseases the occurrence of which may be favored by estradiol
Above has been a lot of mention about what happens when a patient becomes deficient in estradiol. The opposite state - an excess of this hormone - is also definitely not beneficial. Hyperestrogenism can lead to several different female cancers, including breast cancer, ovarian cancer and endometrial cancer.
Estradiol: use in medicine
Estradiol - due to its various activities - is widely used in medicine. This hormone is present in many forms of contraception - it is essentially one of the basic hormonal components in the prevention of conception. Preparations with estradiol are also used as hormone replacement therapy - they are used primarily in women who experience significant symptoms related to menopause. In addition to the aforementioned group of patients, hormone replacement therapy is also used in patients who perform gender reassignment from male to female.
About the authorBow. Tomasz NęckiA graduate of medicine at the Medical University of Poznań. An admirer of the Polish sea (most willingly strolling along its shores with headphones in his ears), cats and books. In working with patients, he focuses on always listening to them and spending as much time as they need.Read more articles by this author