Antiestrogens are substances that inhibit the effects or the production of estrogens. Estrogens are a group of hormones responsible for the development and maintenance of female sex characteristics. These compounds are critical in the treatment of certain medical conditions and in the realm of medical research, especially in areas concerning reproductive health and oncology.
Antiestrogens work by blocking the production or utilization of estrogens, or by inhibiting their effects. These agents can have a significant impact on cells, especially those that are estrogen receptor (ER) positive. For instance, antiestrogens like tamoxifen can promote an invasive phenotype in ER-positive breast cancer cells when intercellular adhesion is deficient.
Distinction from Aromatase Inhibitors[edit | edit source]
Although aromatase inhibitors might sometimes be classified as antiestrogens due to their ability to reduce estrogen production, they are often regarded as a separate class. The term "antiestrogen" is typically reserved for agents that diminish the response to estrogen, rather than those that reduce its production.
Aromatase inhibitors function by decreasing the production of estrogen in the body. They achieve this by targeting and inhibiting the enzyme aromatase, which is crucial for the conversion of androgens to estrogens. Their mechanism differs from that of typical antiestrogens which block the estrogen receptors or the effects of estrogen on these receptors.
Antiestrogens are primarily used in the treatment of estrogen receptor-positive breast cancers. They can also be utilized in fertility treatments and in certain conditions where estrogen production or activity needs to be suppressed.
| Estrogens and antiestrogens |
| Estrogens |
|
| ER
agonists | * Steroidal: Alfatradiol
- Certain androgens/anabolic steroids (e.g., testosterone, testosterone esters, methyltestosterone, metandienone, nandrolone esters) (via estrogenic metabolites)
- Certain progestins (e.g., norethisterone, noretynodrel, etynodiol diacetate, tibolone)
- Clomestrone
- Cloxestradiol acetate
- Conjugated estriol
- Conjugated estrogens
- Epiestriol
- Epimestrol
- Esterified estrogens
- Estetrol†
- Estradiol
- Estradiol esters (e.g., estradiol acetate, estradiol benzoate, estradiol cypionate, estradiol enanthate, estradiol undecylate, estradiol valerate, polyestradiol phosphate, estradiol ester mixtures (Climacteron))
- Estramustine phosphate
- Estriol
- Estriol esters (e.g., estriol succinate, polyestriol phosphate)
- Estrogenic substances
- Estrone
- Estrone esters
- Ethinylestradiol#
- Hydroxyestrone diacetate
- Mestranol
- Methylestradiol
- Moxestrol
- Nilestriol
- Prasterone (dehydroepiandrosterone; DHEA)
- Promestriene
- Quinestradol
- Quinestrol
|
| Progonadotropins | |
|
|
| Antiestrogens |
|
ER
antagonists
(incl. SERMs
/SERDs
) | |
| Aromatase inhibitors | |
| Antigonadotropins | * Androgens/ anabolic steroids (e.g., testosterone, testosterone esters, nandrolone esters, oxandrolone, fluoxymesterone)
- D2 receptor antagonists (prolactin releasers) (e.g., domperidone, metoclopramide, risperidone, haloperidol, chlorpromazine, sulpiride)
- GnRH
agonists (e.g., leuprorelin, goserelin)
- GnRH
antagonists (e.g., cetrorelix, elagolix)
- Progestogens (e.g., chlormadinone acetate, cyproterone acetate, gestonorone caproate, hydroxyprogesterone caproate, medroxyprogesterone acetate, megestrol acetate)
|
| Others | * Mixed mechanism of action: Danazol
|
|
|
|
| Estrogen receptor modulators |
| ER
|
|
| Agonists | * Steroidal: 2-Hydroxyestradiol
- 2-Hydroxyestrone
- 3-Methyl-19-methyleneandrosta-3,5-dien-17β-ol
- 3α-Androstanediol
- 3α,5α-Dihydrolevonorgestrel
- 3β,5α-Dihydrolevonorgestrel
- 3α-Hydroxytibolone
- 3β-Hydroxytibolone
- 3β-Androstanediol
- 4-Androstenediol
- 4-Androstenedione
- 4-Fluoroestradiol
- 4-Hydroxyestradiol
- 4-Hydroxyestrone
- 4-Methoxyestradiol
- 4-Methoxyestrone
- 5-Androstenediol
- 7-Oxo-DHEA
- 7α-Hydroxy-DHEA
- 7α-Methylestradiol
- 7β-Hydroxyepiandrosterone
- 8,9-Dehydroestradiol
- 8,9-Dehydroestrone
- 8β-VE2
- 10β,17β-Dihydroxyestra-1,4-dien-3-one (DHED)
- 11β-Chloromethylestradiol
- 11β-Methoxyestradiol
- 15α-Hydroxyestradiol
- 16-Ketoestradiol
- 16-Ketoestrone
- 16α-Fluoroestradiol
- 16α-Hydroxy-DHEA
- 16α-Hydroxyestrone
- 16α-Iodoestradiol
- 16α-LE2
- 16β-Hydroxyestrone
- 16β,17α-Epiestriol (16β-hydroxy-17α-estradiol)
- 17α-Estradiol (alfatradiol)
- 17α-Dihydroequilenin
- 17α-Dihydroequilin
- 17α-Epiestriol (16α-hydroxy-17α-estradiol)
- 17α-Ethynyl-3α-androstanediol
- 17α-Ethynyl-3β-androstanediol
- 17β-Dihydroequilenin
- 17β-Dihydroequilin
- 17β-Methyl-17α-dihydroequilenin
- Abiraterone
- Abiraterone acetate
- Alestramustine
- Almestrone
- Anabolic steroids (e.g., testosterone and esters, methyltestosterone, metandienone (methandrostenolone), nandrolone and esters, many others; via estrogenic metabolites)
- Atrimustine
- Bolandiol
- Bolandiol dipropionate
- Butolame
- Clomestrone
- Cloxestradiol
- Conjugated estriol
- Conjugated estrogens
- Cyclodiol
- Cyclotriol
- DHEA
- DHEA-S
- ent-Estradiol
- Epiestriol (16β-epiestriol, 16β-hydroxy-17β-estradiol)
- Epimestrol
- Equilenin
- Equilin
- ERA-63 (ORG-37663)
- Esterified estrogens
- Estetrol
- Estradiol
- Estramustine
- Estramustine phosphate
- Estrapronicate
- Estrazinol
- Estriol
- Estrofurate
- Estrogenic substances
- Estromustine
- Estrone
- Etamestrol (eptamestrol)
- Ethinylandrostenediol
- Ethinylestradiol
- Ethinylestriol
- Ethylestradiol
- Etynodiol
- Etynodiol diacetate
- Hexolame
- Hippulin
- Hydroxyestrone diacetate
- Lynestrenol
- Lynestrenol phenylpropionate
- Mestranol
- Methylestradiol
- Moxestrol
- Mytatrienediol
- Nilestriol
- Norethisterone
- Noretynodrel
- Orestrate
- Pentolame
- Prodiame
- Prolame
- Promestriene
- RU-16117
- Quinestradol
- Quinestrol
- Tibolone
- Xenoestrogens: Anise-related (e.g., anethole, anol, dianethole, dianol, photoanethole)
- Chalconoids (e.g., isoliquiritigenin, phloretin, phlorizin (phloridzin), wedelolactone)
- Coumestans (e.g., coumestrol, psoralidin)
- Flavonoids (incl. 7,8-DHF, 8-prenylnaringenin, apigenin, baicalein, baicalin, biochanin A, calycosin, catechin, daidzein, daidzin, ECG, EGCG, epicatechin, equol, formononetin, glabrene, glabridin, genistein, genistin, glycitein, kaempferol, liquiritigenin, mirificin, myricetin, naringenin, penduletin, pinocembrin, prunetin, puerarin, quercetin, tectoridin, tectorigenin)
- Lavender oil
- Lignans (e.g., enterodiol, enterolactone, nyasol (cis-hinokiresinol))
- Metalloestrogens (e.g., cadmium)
- Pesticides (e.g., alternariol, dieldrin, endosulfan, fenarimol, HPTE, methiocarb, methoxychlor, triclocarban, triclosan)
- Phytosteroids (e.g., digitoxin (digitalis), diosgenin, guggulsterone)
- Phytosterols (e.g., β-sitosterol, campesterol, stigmasterol)
- Resorcylic acid lactones (e.g., zearalanone, α-zearalenol, β-zearalenol, zearalenone, zeranol (α-zearalanol), taleranol (teranol, β-zearalanol))
- Steroid-like (e.g., deoxymiroestrol, miroestrol)
- Stilbenoids (e.g., resveratrol, rhaponticin)
- Synthetic xenoestrogens (e.g., alkylphenols, bisphenols (e.g., BPA, BPF, BPS), DDT, parabens, PBBs, PHBA, phthalates, PCBs)
- Others (e.g., agnuside, rotundifuran)
|
Mixed
(SERMs
) | |
| Antagonists | |
|
|
| GPER
|
|
| Agonists | |
| Antagonists | |
| Unknown | |
|
|
|
| This article is a medical stub. You can help WikiMD by expanding it!
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