Estriol. Note two hydroxyl (-OH) groups attached to the D ring (rightmost ring).

Estradiol. Note one hydroxyl group attached to the D ring. The 'di' refers both to this hydroxyl and the one on the A ring (leftmost).

Estrone. Note the ketone (=O) group attached to the D ring.

Estrogens (alternate spelling: oestrogens) are a group of steroid compounds, named for their importance in the estrous cycle, and functioning as the primary female sex hormone. While estrogens are present in both men and women, they are usually present at significantly higher levels in women of reproductive age. They promote the development of female secondary sex characteristics, such as breasts, and are also involved in the thickening of the endometrium and other aspects of regulating the menstrual cycle. In males estrogen regulates certain functions of the reproductive system important to the maturation of sperm. ^{[1] [2]} and may be neccesary for a healthy libido ^[3]. Like all steroid hormones, estrogens readily diffuse across the cell membrane; inside the cell, they interact with estrogen receptors.^[4] Image File history File links Download high resolution version (2928x1613, 15 KB) * Description: Chemical structure of Estriol. ... Image File history File links Download high resolution version (2928x1613, 15 KB) * Description: Chemical structure of Estriol. ... Chemical structure of estriol Estriol (also oestriol) is one of the three main estrogens produced by the human body. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... Image File history File links Download high-resolution version (1100x704, 39 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Estrogen Estradiol Estramustine ... Image File history File links Download high-resolution version (1100x704, 39 KB) File links The following pages on the English Wikipedia link to this file (pages on other projects are not listed): Estrogen Estradiol Estramustine ... Estradiol (17β-estradiol) (also oestradiol) is a sex hormone. ... // Hydroxyl group The term hydroxyl group is used to describe the functional group -OH when it is a substituent in an organic compound. ... Image File history File links Estrone. ... Image File history File links Estrone. ... Estrone (also oestrone) is an estrogenic hormone secreted by the ovary. ... Ketone group A ketone is either the functional group characterized by a carbonyl group linked to two other carbon atoms or a chemical compound that contains this functional group. ... Steroid skeleton of lanosterol. ... The estrous cycle (also oestrous cycle; originally derived from Latin oestrus) refers to the recurring physiologic changes that are induced by reproductive hormones in most mammalian placental females. ... The hand mirror and comb of the Roman Goddess Venus is often used to represent the female sex. ... This article or section does not cite its references or sources. ... A hormone (from Greek horman - to set in motion) is a chemical messenger from one cell (or group of cells) to another. ... A man is a male human. ... Diverse women. ... A peafowl displays its long, colored feathers, an example of its secondary sexual characteristics. ... A pregnant womans breasts. ... The endometrium is the inner uterine membrane in mammals which is developed in preparation for the implantation of a fertilized egg upon its arrival into the uterus. ... Menstrual cycle The menstrual cycle is a recurring cycle of physiological changes in the females of some animal species that is associated with reproductive fertility. ... Steroid hormones are steroids which act as hormones. ... This article or section does not cite its references or sources. ... Illustration of a cell membrane The cell membrane, also called the plasma membrane or plasmalemma, is a semipermeable lipid layer surrounding the cytoplasm of all living cells. ... The estrogen receptor is a receptor for estradiol (the main endogenous estrogen); it is located intracellularly, in parallel with other steroid hormone receptors. ...

The three major naturally occurring estrogens in women are estradiol, estriol, and estrone. From menarche to menopause the primary estrogen is 17β-estradiol. In the body these are all produced from androgens through actions of enzymes. Estradiol is produced from testosterone and estrone from androstenedione. Estrone is weaker than estradiol, and in postmenopausal women more estrone is present than estradiol. A range of synthetic and natural substances have been identified that also possess estrogenic activity.^[5] Synthetic substances of this kind are known as xenoestrogens, while natural plant products with estrogenic activity are called phytoestrogens. Estradiol (17β-estradiol) (also oestradiol) is a sex hormone. ... Chemical structure of estriol Estriol (also oestriol) is one of the three main estrogens produced by the human body. ... Estrone (also oestrone) is an estrogenic hormone secreted by the ovary. ... Menarche (IPA: ) is the first menstrual period, or first menstrual bleeding. ... Menopause is the physiological cessation of menstrual cycles associated with advancing age in species that experience such cycles. ... Estradiol (17β-estradiol) (also oestradiol) is a sex hormone. ... Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors. ... Ribbon diagram of the enzyme TIM, surrounded by the space-filling model of the protein. ... Testosterone is a steroid hormone from the androgen group. ... Androstenedione (also known as 4-androstenedione) is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol. ... Xenoestrogens are synthetic substances that differ from those produced by living organisms and imitate or enhance the effect of estrogens. ... Phytoestrogens are plant compounds with effects similar to those of estrogen, although somewhat weaker. ...

Estrogens are used as part of some oral contraceptives and also in estrogen replacement therapy of postmenopausal women. The combined oral contraceptive pill, often referred to as the Pill, is a combination of an estrogen (oestrogen) and a progestin (progestogen), taken by mouth to inhibit normal fertility. ... Menopause is the physiological cessation of menstrual cycles associated with advancing age in species that experience such cycles. ...

Estrogen production

Estrogen is produced primarily by developing follicles in the ovaries, the corpus luteum, and the placenta. Follicle-stimulating hormone (FSH) and luteinizing hormone (LH) stimulate the production of estrogen in the ovaries. Some estrogens are also produced in smaller amounts by other tissues such as the liver, adrenal glands, and the breasts. These secondary sources of estrogen are especially important in postmenopausal women. Ovarian follicles or Graafian follicles (after Regnier de Graaf) are the roughly spherical cell aggregations in the ovary containing an ovum and from which the egg is released during ovulation. ... The corpus luteum (Latin for yellow body) is a small, temporary endocrine structure in animals. ... The placenta is an ephemeral (temporary) organ present only in female placental vertebrates during gestation (pregnancy). ... Follicle stimulating hormone Follicle stimulating hormone (FSH) is a hormone synthesised and secreted by gonadotropes in the anterior pituitary gland. ... Luteinizing hormone (LH) is a hormone synthesized and secreted by gonadotropes in the anterior lobe of the pituitary gland. ... Human female internal reproductive anatomy Ovaries are egg-producing reproductive organs found in female organisms. ... The liver is an organ in some animals, including mammals (and therefore humans), birds, and reptiles. ... Grays Fig. ... A pregnant womans breasts. ...

Synthesis of estrogens starts in theca interna cells in the ovary, by the synthesis of androstenedione from cholesterol. Androstenedione is a substance of moderate androgenic activity. This compound crosses the basal membrane into the surrounding granulosa cells, where it is converted to estrone or estradiol, either immediately or through testosterone. The conversion of testosterone to estradiol, and of androstenedione to estrone, is catalyzed by the enzyme aromatase. In biology, folliculogenesis refers to the maturation of the ovarian follicle, a densely-packed shell of somatic cells that contains an immature oocyte. ... Androstenedione (also known as 4-androstenedione) is a 19-carbon steroid hormone produced in the adrenal glands and the gonads as an intermediate step in the biochemical pathway that produces the androgen testosterone and the estrogens estrone and estradiol. ... Cholesterol is a sterol (a combination steroid and alcohol) and a lipid found in the cell membranes of all body tissues, and transported in the blood plasma of all animals. ... Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors. ... A granulosa cell is a supporting cell for the developing female gamete in the ovary of mammals. ... Testosterone is a steroid hormone from the androgen group. ... Aromatase belongs to the group of cytochrome P450 enzymes (EC 1. ...

Estradiol levels vary through the menstrual cycle, with levels highest just before ovulation. Ovulation is the process in the menstrual cycle by which a mature ovarian follicle ruptures and discharges an ovum (also known as an oocyte, female gamete, or casually, an egg) that participates in reproduction. ...

• Structural
  • promote formation of female secondary sex characteristics
  • stimulate endometrial growth
  • increase uterine growth
  • maintenance of vessel and skin
  • reduce bone resorption, increase bone formation
• protein synthesis
  • increase hepatic production of binding proteins
• coagulation
  • increase circulating level of factors 2,7,9,10, antithrombin III, plasminogen
  • increase platelet adhesiveness
• Lipid
  • increase HDL, triglyceride, fat depositition
  • decrease LDL
• Fluid balance
  • salt and water retention
• gastrointestinal tract
  • reduce bowel motility
  • increase cholesterol in bile
• Cancer
  • About 80% of breast cancers, once established, rely on supplies of the hormone estrogen to grow: they are known as hormone-sensitive or hormone-receptor-positive cancers.^[6] Suppression of production in the body of estrogen is a treatment for these cancers.

Studies have found better correlation between sexual desire and androgen levels than for estrogen levels.^[7] The endometrium is the inner uterine membrane in mammals which is developed in preparation for the implantation of a fertilized egg upon its arrival into the uterus. ... The uterus or womb is the major female reproductive organ of most mammals, including humans. ... Bone resorption is the process by which osteoclasts break down bone and release the minerals. ... A representation of the 3D structure of myoglobin, showing coloured alpha helices. ... The liver is an organ in some animals, including mammals (and therefore humans), birds, and reptiles. ... The coagulation of blood is a complex process during which blood forms solid clots. ... Image:Antithrombin. ... Plasmin is an important degrading enzyme (EC 3. ... A 250 ml bag of newly collected platelets. ... High-density lipoproteins (HDL) form a class of lipoproteins, varying somewhat in their size (8–11 nm in diameter), that carry cholesterol from the bodys tissues to the liver. ... It has been suggested that Medium Chain Triglycerides be merged into this article or section. ... Low-density lipoprotein (LDL) is a class of lipoprotein particles that varies in size (18-25 nm in diameter) and contents (while carrying fatty acid molecules in blood and around the body). ... Cholesterol is a sterol (a combination steroid and alcohol) and a lipid found in the cell membranes of all body tissues, and transported in the blood plasma of all animals. ... Bile (or gall) is a bitter, greenish-yellow alkaline fluid secreted by hepatocytes from the liver of most vertebrates. ... Breast cancer is cancer of breast tissue. ... Androgen is the generic term for any natural or synthetic compound, usually a steroid hormone, that stimulates or controls the development and maintenance of masculine characteristics in vertebrates by binding to androgen receptors. ...

In studies involving mice and rats, it was found that lung function may be improved by estrogen. In one study involving 16 animals, female mice that had their ovaries removed to deprive them of estrogen lost 45 percent of their working alveoli from their lungs. Upon receiving estrogen, the mice recovered full lung function.^[8] The alveoli (singular:alveolus), tiny hollow sacs which are continuous with the airways, are the sites of gas exchange with the blood. ...

Medical applications

Since estrogen circulating in the blood can negatively feed-back to reduce circulating levels of FSH and LH, most oral contraceptives contain a synthetic estrogen, along with a synthetic progestin. Negative feedback (shortened to NFB) is a type of feedback in which the system responds in an opposite direction to the perturbation. ... The combined oral contraceptive pill, often referred to as the Pill, is a combination of an estrogen (oestrogen) and a progestin (progestogen), taken by mouth to inhibit normal fertility. ... A progestin is a synthetic progestagen. ...

In hormone replacement therapy, estrogen and other hormones are given to postmenopausal women in order to prevent osteoporosis as well as treat the symptoms of menopause such as hot flashes, vaginal dryness, urinary stress incontinence, chilly sensations, dizziness, fatigue, irritability, and sweating. Fractures of the spine, wrist, and hips decrease by 50-70% and spinal bone density increases by ~5% in those women treated with estrogen within 3 years of the onset of menopause and for 5-10 years thereafter. Standard therapy is 0.625 mg/day of conjugated estrogens (such as is in Premarin), but the dose can range from 0.3 mg/day to 1.25 mg/day. Estrogen replacement therapy also has favorable effects on serum cholesterol levels and is claimed to dramatically reduce the incidence of cardiovascular disease. There are, however, risks associated with estrogen therapy. Among the older postmenopausal women studied as part of the Women's Health Initiative (WHI), an orally-administered estrogen supplement has been associated with an increased risk of dangerous blood clotting. The WHI studies used one type of estrogen supplement, a high oral dose of conjugated equine estrogens (Premarin alone and with Provera as Prempro)[1]. Research is underway to determine if risks of estrogen supplement use are the same for all methods of delivery. In particular, estrogen applied topically may have a different spectrum of side-effects than when administered orally[2], and transdermal oestrogens do not affect clotting as they are absorbed directly into the systemic circulation, avoiding first-pass metabolism in the liver. This route of administration is thus preferred in women with a history of thrombo-embolic disease. Hormone replacement therapy (HRT) is a system of medical treatment for perimenopausal and postmenopausal women, based on the assumption that it may prevent discomfort and health problems caused by diminished circulating estrogen hormones. ... Osteoporosis is a disease of bone in which the bone mineral density (BMD) is reduced, bone microarchitecture is disrupted, and the amount and variety of non-collagenous proteins in bone is altered. ... The Womens Health Initiative (WHI) was initiated by the National Institutes of Health (NIH) in 1991. ... Coagulation is the thickening or congealing of any liquid into solid clots. ... Premarin is a mixture of estrogens isolated from mares urine (PREgnant MARes urINe) made by Wyeth Pharmaceuticals. ... In medicine, a topical medication is applied to body surfaces such as the skin or mucous membranes such as the vagina, nasopharynx, or the eye. ... Thrombosis is the formation of a clot or thrombus inside a blood vessel, obstructing the flow of blood through the circulatory system. ...

Estrogen is also used in the therapy of vaginal atrophy, hypoestrogenism (as a result of hypogonadism, castration, or primary ovarian failure), amenorrhea, dysmenorrhea, and oligomenorrhea. Estrogens can also be used to suppress lactation after child birth. Kittens nursing Lactation describes the secretion of milk from the mammary glands, the process of providing that milk to the young, and the period of time that a mother lactates to feed her young. ...

Hormone-receptor-positive breast cancers are treated with drugs which suppress production in the body of estrogen[3]. This technique, in the context of treatment of breast cancer, is know variously as hormonal therapy, hormone therapy, or anti-estrogen therapy (not to be confused with hormone replacement therapy). Breast cancer is cancer of breast tissue. ... This article needs cleanup. ... In medicine, hormone therapy is the use of hormones in medical treatment and covers various types of hormones including growth hormones and sex hormones. ... Hormone replacement therapy (HRT) is a system of medical treatment for perimenopausal and postmenopausal women, based on the assumption that it may prevent discomfort and health problems caused by diminished circulating estrogen hormones. ...

At one time, estrogen was used to induce growth attenuation in tall girls^[9]. Recently, estrogen-induced growth attenuation was used as part of the controversial Ashley Treatment to keep a developmentally disabled girl from growing to adult size^[10]. Growth attenuation is a medical treatment which involves adminstering estrogen to cause closure of the bone plates, resulting in stunted growth. ... The Ashley Treatment refers to a controversial set of medical procedures undergone by a Seattle child, Ashley X. Ashley, born in 1997, was a child with severe developmental disabilities due to static encephalopathy of unknown etiology. ... Developmental disability is a term used to describe severe, life-long disabilities attributable to mental and/or physical impairments, manifested before the age of 22. ...

Health risks and warning labels

The labeling of estrogen-only products in the U.S. includes a boxed warning that unopposed estrogen (without progestagen) therapy increases the risk of endometrial cancer. In the United States, a black box warning is a type of warning that appears on prescription drugs that may cause serious side effects. ... Progestagens (also spelled progestogens or gestagens) are hormones which produce effects similar to progesterone, the only natural progestagen. ... Endometrial cancer involves cancerous growth of the endometrium (lining of the uterus). ...

Based on a review of data from the WHI, on January 8, 2003 the FDA changed the labeling of all estrogen and estrogen with progestin products for use by postmenopausal women to include a new boxed warning about cardiovascular and other risks. The estrogen-alone substudy of the WHI reported an increased risk of stroke and deep vein thrombosis (DVT) in postmenopausal women 50 years of age or older and an increased risk of dementia in postmenopausal women 65 years of age or older using 0.625 mg of Premarin conjugated equine estrogens (CEE). The estrogen-plus-progestin substudy of the WHI reported an increased risk of myocardial infarction, stroke, invasive breast cancer, pulmonary emboli and DVT in postmenopausal women 50 years of age or older and an increased risk of dementia in postmenopausal women 65 years of age or older using 0.625 mg of CEE with 2.5 mg of the progestin medroxyprogesterone acetate (MPA).^[11][12][13] A stroke, also known as cerebrovascular accident (CVA),[1] is an acute neurological injury in which the blood supply to a part of the brain is interrupted. ... Deep-vein thrombosis, also known as deep-venous thrombosis or DVT, is the formation of a blood clot (thrombus) in a deep vein. ... Dementia (from Latin de- apart, away + mens (genitive mentis) mind) is the progressive decline in cognitive function due to damage or disease in the brain beyond what might be expected from normal aging. ... Acute myocardial infarction (AMI or MI), commonly known as a heart attack, is a disease state that occurs when the blood supply to a part of the heart is interrupted. ... Breast cancer is cancer of breast tissue. ... A pulmonary embolism (thromboembolism) occurs when a blood clot, generally a venous thrombus, becomes dislodged from its site of formation and embolizes to the arterial blood supply of one of the lungs. ... Medroxyprogesterone is a molecule used in hormonal contraceptives. ...

Estrogens in cosmetics

Some hair shampoos on the market include estrogens and placental extracts; others contain phytoestrogens. There are case reports of young children developing breasts after exposure to these shampoos. The FDA is aware of these reports but does not consider them of concern to consumers.^[14] These products are especially popular with African-American consumers.^[15][16] Several shampoos on a shower window Shampoo (Hindi: शम्पू) is a hair care product used for the removal of oils, dirt, skin particles, environmental pollution and/or other contaminant particles that gradually build up in hair. ... The placenta is an ephemeral (temporary) organ present only in female placental vertebrates during gestation (pregnancy). ... The Food and Drug Administration (FDA) is an agency of the United States Department of Health and Human Services and is responsible for regulating food (humans and animal), dietary supplements, drugs (human and animal), cosmetics, medical devices (human and animal) and radiation emitting devices (including non-medical devices), biologics, and...

On September 9, 1993, the FDA determined that all topically-applied hormone-containing drug products for OTC human use are not generally recognized as safe and effective and are misbranded. An accompanying proposed rule deals with cosmetics, concluding that any use of natural estrogens in a cosmetic product makes the product an unapproved new drug and that any cosmetic using the term "hormone" in the text of its labeling or in its ingredient statement makes an implied drug claim, subjecting such a product to regulatory action.^[17] Over-the-counter (OTC) drugs are medicines that may be sold without a prescription and without a visit to a medical professional, in contrast to prescription drugs. ...

In addition to being considered misbranded drugs, products claiming to contain placental extract may also be deemed to be misbranded cosmetics if the extract has been prepared from placentas from which the hormones and other biologically active substances have been removed and the extracted substance consists principally of protein. The FDA recommends that this substance be identified by a name other than "placental extract" and describing its composition more accurately because consumers associate the name "placental extract" with a therapeutic use of some biological activity.^[17]

History

The existence and effects of estrogen were established from 1923 to 1938 in which the formulation was led by a group of scientists instead of pharmaceutical companies. Thereafter, the market for hormonal drug research opened up.

The “first orally effective estrogen”, Emmenin, derived from the late-pregnancy urine of Canadian women, was introduced in 1930 by Collip and Ayerst Laboratories (now Wyeth). Estrogens are not water-soluble and cannot be given orally, but the urine was found to contain estriol glucuronide which is water soluble and becomes active in the body after hydrolization. Wyeth, formerly known as American Home Products, is one of the largest pharmaceutical companies in the world. ... Glucuronide is a substance produced by attaching glucuronic acid to another substance with glycosidic bonds. ... Hydrolysis is a chemical reaction or process in which a molecule is split into two parts by reacting with a molecule of water, which has the chemical formula H2O. One of the parts gets an OH from the water molecule and the other part gets an H from the water. ...

Scientists continued to search for new sources of estrogen because of concerns associated with the practicality of introducing the drug into the market. At the same time, a German pharmaceutical drug company, Schering, formulated a similar product as Emmenin that was introduced to German women to treat menopausal symptoms. Schering AG (FWB:SCH, NYSE: SHR) is a research-centered pharmaceutical company founded in 1851. ...

In 1938, British scientists obtained a patent on a newly formulated nonsteroidal estrogen, Diethylstilbestrol (DES), that was cheaper and more powerful than the previously manufactured estrogens. Soon after, concerns over the side effects of DES were raised in scientific journals while the drug manufacturers came together to lobby for governmental approval of DES. It was only until 1941 when estrogen therapy was finally approved by the Food and Drug Administration (FDA) for the treatment of menopausal symptoms. ^[18] Diethylstilbestrol (DES) is a drug, a synthetic nonsteroidal estrogen that was first synthesized in 1938. ... The Food and Drug Administration (FDA) is an agency of the United States Department of Health and Human Services and is responsible for regulating food (humans and animal), dietary supplements, drugs (human and animal), cosmetics, medical devices (human and animal) and radiation emitting devices (including non-medical devices), biologics, and...

References

For the Manfred Mann album, see 2006 (album). ... October 26 is the 299th day of the year (300th in leap years) in the Gregorian Calendar, with 66 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 26 is the 299th day of the year (300th in leap years) in the Gregorian Calendar, with 66 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 26 is the 299th day of the year (300th in leap years) in the Gregorian Calendar, with 66 days remaining. ... The New York Times is a newspaper published in New York City by Arthur Ochs Sulzberger Jr. ... For the Manfred Mann album, see 2006 (album). ... October 24 is the 297th day of the year (298th in leap years) in the Gregorian Calendar, with 68 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 27 is the 300th day of the year (301st in leap years) in the Gregorian Calendar, with 65 days remaining. ...

See also

• Atrophic vaginitis
• Endocrinology
• Equol
• Equilin
• Estradiol
• Estrogen receptor
• Premarin
• Hormone Replacement Therapy
• Progesterone
• Progestin

References

For the Manfred Mann album, see 2006 (album). ... October 26 is the 299th day of the year (300th in leap years) in the Gregorian Calendar, with 66 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 26 is the 299th day of the year (300th in leap years) in the Gregorian Calendar, with 66 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 26 is the 299th day of the year (300th in leap years) in the Gregorian Calendar, with 66 days remaining. ... The New York Times is a newspaper published in New York City by Arthur Ochs Sulzberger Jr. ... For the Manfred Mann album, see 2006 (album). ... October 24 is the 297th day of the year (298th in leap years) in the Gregorian Calendar, with 68 days remaining. ... For the Manfred Mann album, see 2006 (album). ... October 27 is the 300th day of the year (301st in leap years) in the Gregorian Calendar, with 65 days remaining. ...

External links and further reading

• MedlinePlus Drug Information: Estrogen information on estrogen-only prescription drugs from the U.S. National Library of Medicine
• Nussey and Whitehead: Endocrinology, an integrated approach, Taylor and Francis 2001. Free online textbook.