Estradiol is a steroid hormone made by cholesterol and is one of four estrogen hormones(the most important one) naturally produced in the body. While men and women have estradiol, and it has a role in both of their bodies, women have much higher levels of the hormone than men.
There are three major endogenous estrogens that have estrogenic hormonal activity: estrone (E1), estradiol (E2), and estriol (E3).
Estrone (E1): the only estrogen your body makes after menopause (when menstrual periods stop)
Estradiol (E2): the most common type in women of childbearing age.
Estriol (E3): the main estrogen during pregnancy.
(Another estrogen called estetrol (E4) is produced only during pregnancy and is usually not included in the list since it is not constantly produced).
Although estrogen is known as a female sex hormone, it also plays a role in male growth and development.
Doctors will likely request an estradiol test if they want to find out more about why a person’s sex characteristics are developing in a certain way.
Transgender women may take estradiol as part of their hormone therapy to develop more female characteristics. If so, their doctor may wish to perform regular estradiol tests to monitor their levels.
Estrogens used in therapeutics are well absorbed through the skin, mucous membranes, and the gastrointestinal (GI) tract. The vaginal delivery of estrogens circumvents first-pass metabolism.
Estrogens administered exogenously distribute in a similar fashion to endogenous estrogens. They can be found throughout the body, especially in the sex hormone target organs, such as the breast, ovaries and uterus.
Although estrogen causes an increase in levels of plasma renin and angiotensin. Estrogen-induced increases in angiotensin, causing sodium retention, which is likely to be the mechanism causing hypertension after oral contraceptive treatment.
Estrogen administration to nursing mothers has been shown to decrease the quantity and quality of the milk. Detectable amounts of estrogens have been identified in the milk of mothers receiving this drug.
What Does Oestradiol Do?
Oestradiol has a big role in development of breast tissue and bone and cartilage density. If the body does not have enough estradiol, bone growth and development are slowed, and adults can develop osteoporosis(bone weakness) and it may even cause hyperthyroidism and liver damage. In both sexes, oestradiol is also made in much smaller amounts by fat tissue, brain and walls of blood vessels.
in the female body, Estradiol has several functions.
Its main function in women is to develope and protect the reproductive system. During the menstrual cycle, increased estradiol levels cause the maturation and release of the egg, as well as the thickening of the uterus lining to allow a fertilized egg to implant. Oestradiol is made primarily in the ovaries, so levels go down as women get older and decrease massively in menopause phase.
too much estradiol in females can cause acne, constipation, loss of libido, and depression. when estradiol is too high, they can increase the risk of female infertility, uterine and breast cancer as well as cardiovascular disease. Women with high estradiol levels may experience weight gain and menstrual problems.
Metabolism of estrogens may also be increased by smoking, resulting in a decreased estrogenic effect.
After 12 months of routine exercise, women who decreased body fat by more than 2 percent also had a 16.7 percent reduction in free serum estradiol, a 13.7 percent reduction in serum estradiol, and an 11.9 percent reduction in serum estrone, a less estrogenic form of estrogen.
Girls may experience delayed puberty with low estradiol levels. Mood swings have also been connected to low estradiol levels.
The combined oral contraceptive pill (the pill) contains synthetic forms of both progesterone and oestradiol. The pill works by preventing ovulation, making it nearly 100% effective in preventing pregnancy. As well as preventing ovulation, the synthetic hormones make the cervical mucus thicker and therefore more difficult for the sperm to move through, thereby reducing their chances of getting to the uterus and oviducts. The synthetic oestradiol was added to prevent breakthrough bleeding, which sometimes occurs with the progesterone-only pill (the mini pill). Girls will also encounter problems at puberty such as a delay in, or failure of, breast development, a disrupted or absent menstrual cycle and infertility. Oestradiol also has important roles in the brain, where low levels can cause depression, fatigue and mood swings.
The risk of gallbladder disease appears to be increased 2- to 4-fold in postmenopausal women receiving estrogen replacement therapy. In one study, an increased risk of gallbladder disease occurred after 2 years of use of the drugs and doubled after 4 or 5 years of use. In another study, an increased risk of gallbladder disease was apparent between 6-12 months of use.
In premenopausal females, normal estradiol levels are 30 to 400 pg/ml.
In postmenopausal females, normal estradiol levels are 0 to 30 pg/ml.
the big role of estradiol for men is to helps with bone maintenance, nitric oxide production, and brain function.
Within the testes, some testosterone is changed into oestradiol and this oestradiol is essential for the production of sperm. While men need lower levels than women, they still need to have this hormone.
In men, too much oestradiol can also cause sexual dysfunction, loss of muscle tone, increased body fat and development of female characteristics(like breast tissue also called gynecomastia). Oestradiol becomes more dominant as a man ages and his testosterone production reduces, which scientists think may be a contributing factor in the development of prostate cancer.
Recent data from clinical intervention studies indicate that estradiol may be a stronger determinant of adiposity than testosterone in men, and even short-term estradiol deprivation contributes to fat mass accrual.
In males, normal estradiol levels are 10 to 50 pg/ml.
estradiol and menopause
The effects of estradiol are clearly seen in women experiencing menopause. During this process, women naturally have lower levels of estradiol as the ovaries no longer produce it, causing the menstrual cycles to stop. This change often causes mood swings, vaginal dryness, hot flashes, and night sweats — the symptoms commonly associated with menopause. Over time, lower estradiol levels can lead to osteoporosis.
Until recently, most women going through menopause were treated with estradiol as a form of hormone replacement therapy (HRT) – usually by pill, gel, or patch – to help reduce the symptoms of menopause. While HRT is effective in improving these symptoms, recent studies have shown some risks associated with HRT, such as an increased risk of blood clots, heart disease and stroke, and breast cancer. Women interested in HRT should contact their medical provider, as factors such as age, lifestyle, and medical conditions can affect these risks. There are also non-hormonal options available to help with menopausal symptoms.
The findings of our study indicate that despite decreasing fat mass, physical exercises increase the estradiol level significantly when 12 weeks of exercise protocol is incorporated among the postmenopausal females.
How is oestradiol managed inside our body?
The production of oestradiol in women’s ovaries is controlled by hormones released from both the hypothalamus in the brain and the pituitary: this is called the reproductive axis in the female and is also known as the hypothalamic–pituitary–ovarian (or gonadal) axis. The hypothalamus in the base of the brain releases a hormone called gonadotropin-releasing hormone. Gonadotropin-releasing hormone then acts on the pituitary gland to cause the release of two further hormones, luteinising hormone (LH) and follicle stimulating hormone (FSH).
LH and FSH enter the blood and stimulate the ovary; in particular, LH and FSH act on the cells that surround each egg (these cells plus the egg form a unit called a follicle) stimulating the follicle to grow and develop. In the last stages of growth and development the cells surrounding the egg will produce oestradiol. After the egg has been ovulated, the ovulated follicle will become a corpus luteum. The corpus luteum produces both progesterone and oestradiol and the primary role of these two hormones is to ensure that the lining of the uterus is fully prepared for implantation, if fertilisation occurs. The amount of oestradiol (and progesterone) in the circulation communicates with the hypothalamus and pituitary to control the development of an egg, ovulation and the menstrual cycle.
Three hours of moderate exercise per week significantly reduced circulating estrogens in postmenopausal women, according to a new Public Health Sciences Division study published in the April 15 issue of Cancer Research. The finding may explain why women who exercise regularly lower their risk for breast cancer.
there was a study that examined differences between women who exercised regularly compared with women who limited their activity to stretching. The study targeted postmenopausal women who were sedentary, and overweight or obese at the beginning of the trial.
Within three months of undertaking the five-day per week exercise program, serum levels of estrogens dipped significantly in the more active postmenopausal women.
This study indicates that exercise can lower levels of circulating estrogens and increase levels of a protein called sex hormone binding globulin (SHBG — a blood-borne protein) that binds up free-estrogen in the serum. Increased levels of SHBG act to regulate the circulating levels of free, biologically available estrogens.