Estradiol is characterized by the greatest biological activity among estrogens belonging to the group of steroids. Below we will answer the questions “what is estradiol?” and “what is estradiol used for?”
What is Estradiol?
Estradiol (E2), sometimes spelled oestradiol, is an estrogenic hormone of steroid nature, that is “manufactured” by the ovaries, adrenal cortex, peripheral tissues, placenta, and testes of men. Its molecular formula is C18H24O2. A small percentage of this hormone is produced during the synthesis of testosterone. It helps in maintaining proper functioning of the reproductive system. It belongs to the key female hormones and is also present in males in a small amount. The hormone is also revealed in numerous animal species, most vertebrates, crustaceans, fish and some insects.
In a female body, it’s emitted by ovaries’ follicles & adrenal glands, while during pregnancy the placenta participates in this process. Its production is associated with reactions and various intermediates, namely androstenedione’s formation, its conversion into estrone by aromatase and then, finally, into estradiol. Due to presence of aromatase in hypothalamus, amygdala, preoptic / septal areas and other brain regions, estradiol may be also synthesized in the brain (Azcoitia I, Yague JG, Garcia-Segura LM, Neuroscience, 2011).
The hormone’s level is significantly increased till the 2nd trimester (the complete formation of placenta). After parturition, its rate becomes normal within 5-6 days. The lowest measures (equal to male ones) are diagnosed during menopause period.
Estradiol’s Functions in the Female Organism
It plays crucial role in regulating menstrual and estrous cycles. It’s involved in the formation of women’s sexual characteristics, in particular, hips’ widening, distribution of fat under a special feminine pattern, breast‘ enlargement. It contributes to protecting reproductive tissues (mammary glands, vagina, uterus). It’s amount isn’t stable and constantly changes: when the ovaries are stimulated by FSH, LH and progesterone, when the egg passes the fallopian tubes and when the uterus is preparing for conception.
Its diurnal quantity fluctuation is related to the rhythm of excretion of LH. The peak of activity occurs at 15-18 pm, and the reduction is observed from midnight to 2 before noon.
During procreative age, the level is different at each cycle’s phase. The concentration of estradiol rises and becomes maximal with ovulation. After the release of the egg, its amount immediately decreases and grows again, but with less intensity. The final decline takes place at the end of the yellow body existence.
Minimal levels always happen at the menstrual period’s beginning, while elevated levels are typical for ovulation, when the egg abandons the ovary and moves towards the sperm. Adequate ovulation and successful impregnation are impossible without estradiol. During pregnancy, this hormone is as important as progesterone, being also responsible for supporting childbearing.
Here is a generalized list of estradiol’s functions:
- due work of the reproductive system;
- proper formation of organs;
- determining a female figure type;
- uterus’s, endometrium’s creation;
- assistance in the development of muscles;
- regulation of blood flow in the womb;
- promoting normalization of cholesterol levels;
- replenishment of energy reserves;
- bolstering of the vessels inside the uterus;
- bone structure strengthening;
- keeping up the tone;
- accumulation of fat layer on the belly, haunch and other places.
Phyllis M. Wise, Shotaro Suzuki, and Candice M. Brown (Dialogues in Clinical Neuroscience, 2009) desribed its ability to protect against neurodegeneration and posited its contradictory neuroregenerative actions.
What Does Estradiol Do in the Male Body?
What does estradiol do in the male body? It plays a salient role. Recent studies have shown that it’s essential for spermatogenesis, libido and sexual function in general. At the same time, scientists haven’t indicated its precise role in the functioning of the reproductive system of men. However, they have concluded that the balance of hormones namely testosterone, estradiol and progesterone is an indispensable condition of sexual health and appropriate reproductive operation. Nevertheless, Scottish researchers Hargreave TB, Elton RA, Sweeting VM, and Basralian K. (Fertil Steril., 1988) reported that measuremements of E2 (serum oestradiol) levels aren’t useful in infertility practice.
In addition, estrogens jointly with testosterone model sexual appetite and behavior in male persons. Like in women, estrogens in men handle hydration and maintenance of skin turgor, as well as regulate the formation of skin collagen (elasticity), hair growth, spermatogenesis processes, etc.
What is Estradiol Used For?
This issue concerns medicines based on synthetic estradiol, and doesn’t refer to the natural hormone.
Artificial hormone is applicable for fighting menopausal symptoms like hot flashes & vaginal dryness, burning, thinning hair, night sweats, chills and inflammation. Other uses of this medication include the prevention of osteoporosis in postmenopausal female individuals and estrogen replacement therapy in patients with ovarian disorders or other ailments that lead to a deficiency of endogenous estrogens.
This hormonal substance is sometimes used as an element of therapy in the treatment of cancer in male & female persons. The medication can suit other purposes that haven’t been listed above.
OTC steroid creams based on vegetable analogues of estradiol are also available on the market. These creams are often presented as bioidentical HRT (read more on testosterone replacement therapy). However, doctors warn that these means are not medications approved by the US FDA and regulators in most other countries. Therefore, the state doesn’t actually control the contents of these preparations. The FDA advises consumers to be careful about the claims that these remedies are safer than prescription estrogen-based gels, and to bear in mind that they may have the same health risks and adverse events (i.e. RX creams).
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