EstrogenEstrogen or oestrogen (see spelling differences) is a category of sex hormone responsible for the development and regulation of the female reproductive system and secondary sex characteristics. There are three major endogenous estrogens that have estrogenic hormonal activity: estrone (E1), estradiol (E2), and estriol (E3). Estradiol, an estrane, is the most potent and prevalent. Another estrogen called estetrol (E4) is produced only during pregnancy. Estrogens are synthesized in all vertebrates and some insects.
Estrogen receptorEstrogen receptors (ERs) are a group of proteins found inside cells. They are receptors that are activated by the hormone estrogen (17β-estradiol). Two classes of ER exist: nuclear estrogen receptors (ERα and ERβ), which are members of the nuclear receptor family of intracellular receptors, and membrane estrogen receptors (mERs) (GPER (GPR30), ER-X, and Gq-mER), which are mostly G protein-coupled receptors. This article refers to the former (ER).
Selective estrogen receptor modulatorSelective estrogen receptor modulators (SERMs), also known as estrogen receptor agonist/antagonists (ERAAs), are a class of drugs that act on the estrogen receptor (ER). A characteristic that distinguishes these substances from pure ER agonists and antagonists (that is, full agonists and silent antagonists) is that their action is different in various tissues, thereby granting the possibility to selectively inhibit or stimulate estrogen-like action in various tissues.
Estrogen receptor alphaEstrogen receptor alpha (ERα), also known as NR3A1 (nuclear receptor subfamily 3, group A, member 1), is one of two main types of estrogen receptor, a nuclear receptor (mainly found as a chromatin-binding protein) that is activated by the sex hormone estrogen. In humans, ERα is encoded by the gene ESR1 (EStrogen Receptor 1). The estrogen receptor (ER) is a ligand-activated transcription factor composed of several domains important for hormone binding, DNA binding, and activation of transcription.
Conjugated estrogensConjugated estrogens (CEs), or conjugated equine estrogens (CEEs), sold under the brand name Premarin among others, is an estrogen medication which is used in menopausal hormone therapy and for various other indications. It is a mixture of the sodium salts of estrogen conjugates found in horses, such as estrone sulfate and equilin sulfate. CEEs are available in the form of both natural preparations manufactured from the urine of pregnant mares and fully synthetic replications of the natural preparations.
Membrane estrogen receptorMembrane estrogen receptors (mERs) are a group of receptors which bind estrogen. Unlike the estrogen receptor (ER), a nuclear receptor which mediates its effects via genomic mechanisms, mERs are cell surface receptors which rapidly alter cell signaling via modulation of intracellular signaling cascades. Putative mERs include membrane-associated ERα (mERα) and ERβ (mERβ), GPER (GPR30), GPRC6A, ER-X, ERx and Gq-mER. The mERs have been reviewed.
Endocrine disruptorEndocrine disruptors, sometimes also referred to as hormonally active agents, endocrine disrupting chemicals, or endocrine disrupting compounds are chemicals that can interfere with endocrine (or hormonal) systems. These disruptions can cause cancerous tumors, birth defects, and other developmental disorders. Found in many household and industrial products, endocrine disruptors "interfere with the synthesis, secretion, transport, binding, action, or elimination of natural hormones in the body that are responsible for development, behavior, fertility, and maintenance of homeostasis (normal cell metabolism).
FishA fish (: fish or fishes) is an aquatic, craniate, gill-bearing animal that lacks limbs with digits. Included in this definition are the living hagfish, lampreys, and cartilaginous and bony fish as well as various extinct related groups. Approximately 95% of living fish species are ray-finned fish, belonging to the class Actinopterygii, with around 99% of those being teleosts. The earliest organisms that can be classified as fish were soft-bodied chordates that first appeared during the Cambrian period.
Cell signalingIn biology, cell signaling (cell signalling in British English) or cell communication is the ability of a cell to receive, process, and transmit signals with its environment and with itself. Cell signaling is a fundamental property of all cellular life in prokaryotes and eukaryotes. Signals that originate from outside a cell (or extracellular signals) can be physical agents like mechanical pressure, voltage, temperature, light, or chemical signals (e.g., small molecules, peptides, or gas).
XenoestrogenXenoestrogens are a type of xenohormone that imitates estrogen. They can be either synthetic or natural chemical compounds. Synthetic xenoestrogens include some widely used industrial compounds, such as PCBs, BPA, and phthalates, which have estrogenic effects on a living organism even though they differ chemically from the estrogenic substances produced internally by the endocrine system of any organism. Natural xenoestrogens include phytoestrogens which are plant-derived xenoestrogens.
Estrogen (medication)An estrogen (E) is a type of medication which is used most commonly in hormonal birth control and menopausal hormone therapy, and as part of feminizing hormone therapy for transgender women. They can also be used in the treatment of hormone-sensitive cancers like breast cancer and prostate cancer and for various other indications. Estrogens are used alone or in combination with progestogens. They are available in a wide variety of formulations and for use by many different routes of administration.
EstradiolEstradiol (E2), also spelled oestradiol, is an estrogen steroid hormone and the major female sex hormone. It is involved in the regulation of the estrous and menstrual female reproductive cycles. Estradiol is responsible for the development of female secondary sexual characteristics such as the breasts, widening of the hips and a female-associated pattern of fat distribution. It is also important in the development and maintenance of female reproductive tissues such as the mammary glands, uterus and vagina during puberty, adulthood and pregnancy.
Fish migrationFish migration is mass relocation by fish from one area or body of water to another. Many types of fish migrate on a regular basis, on time scales ranging from daily to annually or longer, and over distances ranging from a few metres to thousands of kilometres. Such migrations are usually done for better feeding or to reproduce, but in other cases the reasons are unclear. Fish migrations involve movements of schools of fish on a scale and duration larger than those arising during normal daily activities.
Estrogen insensitivity syndromeEstrogen insensitivity syndrome (EIS), or estrogen resistance, is a form of congenital estrogen deficiency or hypoestrogenism which is caused by a defective estrogen receptor (ER) – specifically, the estrogen receptor alpha (ERα) – that results in an inability of estrogen to mediate its biological effects in the body. Congenital estrogen deficiency can alternatively be caused by a defect in aromatase, the enzyme responsible for the biosynthesis of estrogens, a condition which is referred to as aromatase deficiency and is similar in symptomatology to EIS.
Growth hormoneGrowth hormone (GH) or somatotropin, also known as human growth hormone (hGH or HGH) in its human form, is a peptide hormone that stimulates growth, cell reproduction, and cell regeneration in humans and other animals. It is thus important in human development. GH also stimulates production of IGF-1 and increases the concentration of glucose and free fatty acids. It is a type of mitogen which is specific only to the receptors on certain types of cells.
High-dose estrogen therapyHigh-dose estrogen therapy (HDE) is a type of hormone therapy in which high doses of estrogens are given. When given in combination with a high dose of progestogen, it has been referred to as pseudopregnancy. It is called this because the estrogen and progestogen levels achieved are in the range of the very high levels of these hormones that occur during pregnancy. HDE and pseudopregnancy have been used in medicine for a number of hormone-dependent indications, such as breast cancer, prostate cancer, and endometriosis, among others.
Estrogen esterAn estrogen ester is an ester of an estrogen, most typically of estradiol but also of other estrogens such as estrone, estriol, and even nonsteroidal estrogens like diethylstilbestrol. Esterification renders estradiol into a prodrug of estradiol with increased resistance to first-pass metabolism, slightly improving its oral bioavailability. In addition, estrogen esters have increased lipophilicity, which results in a longer duration when given by intramuscular or subcutaneous injection due to the formation of a long-lasting local depot in muscle and fat.
Fish farmingFish farming or pisciculture involves commercial breeding of fish, most often for food, in fish tanks or artificial enclosures such as fish ponds. It is a particular type of aquaculture, which is the controlled cultivation and harvesting of aquatic animals such as fish, crustaceans, molluscs and so on, in natural or pseudo-natural environments. A facility that releases juvenile fish into the wild for recreational fishing or to supplement a species' natural numbers is generally referred to as a fish hatchery.
Growth factorA growth factor is a naturally occurring substance capable of stimulating cell proliferation, wound healing, and occasionally cellular differentiation. Usually it is a secreted protein or a steroid hormone. Growth factors are important for regulating a variety of cellular processes. Growth factors typically act as signaling molecules between cells. Examples are cytokines and hormones that bind to specific receptors on the surface of their target cells. They often promote cell differentiation and maturation, which varies between growth factors.
Estradiol (medication)Estradiol (E2) is a medication and naturally occurring steroid hormone. It is an estrogen and is used mainly in menopausal hormone therapy and to treat low sex hormone levels in women. It is also used in hormonal birth control for women, in hormone therapy for transgender women, and in the treatment of hormone-sensitive cancers like prostate cancer in men and breast cancer in women, among other uses.
