Estrone belongs to the group of estrogens and thus to the female sex hormones. It is produced in the ovaries, adrenal gland, and subcutaneous fat.
What is estrone?
Estrone is the main estrogen of post-menopausal women. In addition to estrone, estradiol and estriol are also estrogens. Other spellings for these hormones are estrone, estradiol, and estriol. Actually, estradiol is the most effective estrogen. After menopause, however, the ovaries make less estrogen, so estrone becomes more important. Control of the formation of estrogens is the responsibility of the pituitary gland. The effects of estrone are manifold. Thus, disturbances in estrone balance can also result in many different symptoms.
Function, effects, and tasks
Estrogens and thus estrone are the most important female sex hormones. The main function of estrone before menopause is to promote the maturation of an egg that is capable of fertilization. Estrogens stimulate the growth of the endometrium in the so-called proliferation phase in the first half of the cycle. This proliferation phase begins immediately after menstruation and ends with ovulation. The hormones ensure good blood flow to the mucous membrane and also signal to the pituitary gland that the egg cell is ready to burst. The pituitary then produces luteinizing hormone (LH). Stimulated by the increase in LH, ovulation is triggered. Estrone is therefore indirectly involved in ovulation. However, estrone does not only act in the area of the ovary. Receptors for estrogens are located on various organs, such as the female breast or uterus. From there, the hormones are channeled directly into the cell nucleus and thus influence cell activity. They stimulate the growth of the female reproductive organs. In the bone, estrogens have a protective effect. Thus, too low an estrogen level can lead to bone loss. The hormones also have a stimulating effect on the immune system. It is interesting to note that estrogens in the brain increase hearing sensitivity. When estrogen levels are reduced, hearing ability decreases. In addition, estrogens, and therefore estrone, are important for storing sounds and speech in memory.
Formation, occurrence, properties, and optimal levels
Estrogens belong to the class of steroid hormones and are formed in the ovaries and adrenal cortex. A special feature of estrone is that it can also be obtained in subcutaneous fatty tissue. There, a male hormone (androstenedione) is transformed into the female sex hormone estrone by a chemical conversion process. This plays a particularly important role in the post-menopausal period. In women, after menopause, 95% of the estrone is derived from the hormones DHEA and androstenedione, which are produced in the adrenal cortex and ovary. This is also the reason why the fat content of the abdomen increases in women after menopause. This fatty tissue is needed for the production of estrone. Estrone production and release is controlled by the anterior pituitary gland. The pituitary gland produces follicle stimulating hormone (FSH). FSH is then transported via the bloodstream to the ovaries, where it stimulates the production of estrogens. If the level of estrogens is sufficient, FSH production in the pituitary gland is curbed again. Estrogens are also released according to a specific rhythm. At the beginning of the cycle, the ovaries produce rather little estrone, whereas shortly before ovulation, a lot of estrone is produced. The normal values of estrone depend on the cycle. In the follicular phase, the first phase of the cycle, the estrone level in the blood should be between 25 and 120 ng/l. In the middle of the cycle, the level increases. In mid-cycle, the level usually rises to 60 to 200 ng/l. In the luteal phase, the second half of the cycle, the level should be above 200 ng/l. During menopause, estrone levels settle between 15 and 80 ng/l.
Diseases and disorders
Elevated estrone levels are found particularly in women with polycystic ovary syndrome and in women who are overweight. In polycystic ovary syndrome, there is increased production of male sex hormones in the ovaries and adrenal cortex. These are then increasingly converted to estrone in adipose tissue. Obese female patients have higher estrone levels because they have more fatty tissue. The high estrone levels stimulate the pituitary gland to produce LH. However, the estrogen levels do not decrease again as in a normal cycle, but remain high.The LH levels remain just as high. On the other hand, the pituitary gland releases less FSH. As a result, ovulation no longer occurs or occurs only rarely. Women with PCO and women who are very overweight can therefore not get pregnant or only with great difficulty. If ovulation does not occur, the so-called corpus luteum also does not form. This normally determines the course of the second half of the cycle by producing certain hormones. Consequently, there are cycle disturbances. Menstruation is infrequent, and sometimes it does not occur at all. Without ovulation, the follicles in the ovaries perish. This causes many small scars and the tissue of the ovary undergoes connective tissue remodeling. Consequently, the ovary is damaged and can only insufficiently perform its function as a hormone producer. In Germany, every fifth to tenth woman is affected by polycystic ovary syndrome. During menopause, there is a deficiency of estrone. The so-called estrogen deficiency syndrome is responsible for many of the typical menopausal symptoms. However, estrogen deficiency can also occur as a result of adrenal insufficiency or hormonal contraception. This manifests itself in symptoms such as menstrual irregularities, vaginal dryness, hot flashes, dry eyes or infertility.
