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. Note one Hydroxyl group attached to the D ring. The 'di' refers both to this hydroxyl and the one on the A ring (leftmost).]] . Note the Ketone (=O) group attached to the D ring. ]] Estrogens (alternate spellings: '''oestrogens''' or '''œstrogens''') are a group of Steroid compounds, named for their importance in the Estrous Cycle , and functioning as the primary Female Sex Hormone . Estrogens are used as part of some Oral Contraceptives , in estrogen replacement therapy of Postmenopausal women, and in Hormone Therapy for transsexual women. Like all Steroid Hormone s, estrogens readily Diffuse across the Cell Membrane ; inside the cell, they interact with Estrogen Receptor s.Nussey and Whitehead: '' Endocrinology, an integrated approach '', Taylor and Francis 2001 TYPES OF ESTROGEN The three major naturally occurring estrogens in women are Estradiol , Estriol , and Estrone . In the body these are all produced from Androgen s through actions of Enzyme s.
A range of synthetic and natural substances have been identified that also possess estrogenic activity.1 Synthetic substances of this kind are known as Xenoestrogen s, while natural plant products with estrogenic activity are called Phytoestrogen s. 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 Gland s, and the Breast s. These secondary sources of estrogen are especially important in postmenopausal women. 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 Cell s, 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 . FUNCTIONS 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 Characteristic s, 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. http://www.scienceblog.com/community/older/1997/B/199701564.html http://www.sciencenews.org/pages/sn_arc97/12_6_97/fob1.htm and may be necessary for a healthy libido http://www.phimr.monash.edu.au/news/media_releases/estrogen_vital_for_male_sex_drive.htm - 20k . Estradiol levels vary through the menstrual cycle, with levels highest just before Ovulation .
Studies have found better correlation between sexual desire and androgen levels than for estrogen levels.2 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.3 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 . In . 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. , hormone therapy, or Anti-estrogen Therapy (not to be confused with hormone replacement therapy). Certain foods such as soy may also suppress the effects of estrogen and are used as an alternative to hormone therapy.4 At one time, estrogen was used to induce to keep a Developmentally Disabled girl from growing to adult sizeDaniel F. Gunther and Douglas S. Diekema. Attenuating Growth in Children With Profound Developmental Disability . ''Archives of Pediatrics & Adolescent Medicine'', Vol. 160 No. 10, October 2006.. Under certain circumstances, estrogen may also be used in males for treatment of Prostate Cancer . The evolving role of estrogen therapy in prostate cancer (Clin. Prostate Cancer.) PMID 15046698 Most recently, estrogen has been used in experimental research as a way to treat patients suffering from Bulimia Nervosa , as opposed to Cognitive Behavioral Therapy , which is a typical method of treatment in bulimia cases. The research hypothesizes that the disease may be linked to a hormonal imbalance in the brain, giving rise to the use of estrogen in the experimental treatment. Bulimia May Result from Hormonal Imbalance Estrogen has also been used in studies which indicate that it may be an effective drug for use in the treatment of traumatic liver injury.5 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 . 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).678 ESTROGENS IN COSMETICS Some hair '', 17 October 2006. These products are especially popular with African-American consumers. Shampoos Contain Large Clinical Doses of Estrogen that Will Cause Breast Cysts , ''New Scientist'', April 03, 2002Su-Ting ''et al.'' Hormone-Containing Hair Product Use in Prepubertal Children. ''Pediatrics & Adolescent Medicine'', vol 156, p. 85. January 2002. PMID 11772198 On September 9, 1993, the FDA determined that not all topically-applied hormone-containing drug products for OTC human use are 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.9 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. 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 . 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 . 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, formulated a similar product as Emmenin that was introduced to German women to treat menopausal symptoms. 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. 10 SEE ALSO REFERENCES SEE ALSO
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