Chemical compound
17β-Dihydroequilin |
Clinical data |
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Other names | β-Dihydroequilin; Δ7-17β-Estradiol; 7-Dehydro-17β-estradiol; Estra-1,3,5(10),7-tetraen-3,17β-diol; NSC-12170 |
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Routes of administration | By mouth |
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Drug class | Estrogen |
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Identifiers |
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(9S,13S,14S,17S)-13-Methyl-6,9,11,12,14,15,16,17-octahydrocyclopenta[a]phenanthrene-3,17-diol |
CAS Number | |
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PubChem CID | |
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ChemSpider | |
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UNII | |
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ChEBI | |
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ChEMBL | |
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CompTox Dashboard (EPA) | - DTXSID40871892
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ECHA InfoCard | 100.020.576 |
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Chemical and physical data |
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Formula | C18H22O2 |
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Molar mass | 270.372 g·mol−1 |
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3D model (JSmol) | |
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InChI=1S/C18H22O2/c1-18-9-8-14-13-5-3-12(19)10-11(13)2-4-15(14)16(18)6-7-17(18)20/h3-5,10,14,16-17,19-20H,2,6-9H2,1H3/t14-,16+,17+,18+/m1/s1 Key:NLLMJANWPUQQTA-UBDQQSCGSA-N |
17β-Dihydroequilin is a naturally occurring estrogen sex hormone found in horses as well as a medication.[1][2] As the C3 sulfate ester sodium salt, it is a minor constituent (1.7%) of conjugated estrogens (CEEs; brand name Premarin).[1] However, as equilin, with equilin sulfate being a major component of CEEs, is transformed into 17β-dihydroequilin in the body, analogously to the conversion of estrone into estradiol, 17β-dihydroequilin is, along with estradiol, the most important estrogen responsible for the effects of CEEs.[1]
Pharmacology
Pharmacodynamics
17β-Dihydroequilin is an estrogen, or an agonist of the estrogen receptors (ERs), the ERα and ERβ.[1] In terms of relative binding affinity for the ERs, 17β-dihydroequilin has about 113% and 108% of that of estradiol for the ERα and ERβ, respectively.[1] 17β-Dihydroequilin has about 83% of the relative potency of CEEs in the vagina and 200% of the relative potency of CEEs in the uterus.[1] Of the equine estrogens, it shows the highest estrogenic activity and greatest estrogenic potency.[1]
Like CEEs as a whole, 17β-dihydroequilin has disproportionate effects in certain tissues such as the liver and uterus.[1] Equilin, the second major component of conjugated estrogens after estrone, is reversibly transformed into 17β-dihydroequilin analogously to the transformation of estrone into estradiol.[1] However, whereas the balance of mutual interconversion of estrone and estradiol is largely shifted in the direction of estrone, it is nearly equal in the case of equilin and 17β-dihydroequilin.[1] As such, although 17β-dihydroequilin is only a minor constituent of CEEs, it is, along with estradiol, the most important estrogen relevant to the estrogenic activity of the medication.[1]
Relative oral potencies of estrogens Estrogen | HFTooltip Hot flashes | VETooltip Vaginal epithelium | UCaTooltip Urinary calcium | FSHTooltip Follicle-stimulating hormone | LHTooltip Luteinizing hormone | HDLTooltip High-density lipoprotein-CTooltip Cholesterol | SHBGTooltip Sex hormone-binding globulin | CBGTooltip Corticosteroid-binding globulin | AGTTooltip Angiotensinogen | Liver |
Estradiol | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 | 1.0 |
Estrone | ? | ? | ? | 0.3 | 0.3 | ? | ? | ? | ? | ? |
Estriol | 0.3 | 0.3 | 0.1 | 0.3 | 0.3 | 0.2 | ? | ? | ? | 0.67 |
Estrone sulfate | ? | 0.9 | 0.9 | 0.8–0.9 | 0.9 | 0.5 | 0.9 | 0.5–0.7 | 1.4–1.5 | 0.56–1.7 |
Conjugated estrogens | 1.2 | 1.5 | 2.0 | 1.1–1.3 | 1.0 | 1.5 | 3.0–3.2 | 1.3–1.5 | 5.0 | 1.3–4.5 |
Equilin sulfate | ? | ? | 1.0 | ? | ? | 6.0 | 7.5 | 6.0 | 7.5 | ? |
Ethinylestradiol | 120 | 150 | 400 | 60–150 | 100 | 400 | 500–600 | 500–600 | 350 | 2.9–5.0 |
Diethylstilbestrol | ? | ? | ? | 2.9–3.4 | ? | ? | 26–28 | 25–37 | 20 | 5.7–7.5 |
Sources and footnotes Notes: Values are ratios, with estradiol as standard (i.e., 1.0). Abbreviations: HF = Clinical relief of hot flashes. VE = Increased proliferation of vaginal epithelium. UCa = Decrease in UCaTooltip urinary calcium. FSH = Suppression of FSHTooltip follicle-stimulating hormone levels. LH = Suppression of LHTooltip luteinizing hormone levels. HDL- C, SHBG, CBG, and AGT = Increase in the serum levels of these liver proteins. Liver = Ratio of liver estrogenic effects to general/systemic estrogenic effects (hot flashes/ gonadotropins). Sources: See template. |
Pharmacokinetics
17β-Dihydroequilin has about 30% of the relative binding affinity of testosterone for sex hormone-binding globulin (SHBG), relative to 50% for estradiol.[1] The metabolic clearance rate of 17β-dihydroequilin is 1,250 L/day/m2, relative to 580 L/day/m2 for estradiol.[1]
Chemistry
17β-Dihydroequilin, or simply β-dihydroequilin, also known as δ7-17β-estradiol or as 7-dehydro-17β-estradiol, as well as estra-1,3,5(10),7-tetraen-3,17β-diol, is a naturally occurring estrane steroid and an analogue of estradiol.[1] In terms of chemical structure and pharmacology, equilin (δ7-estrone) is to 17β-dihydroequilin as estrone is to estradiol.[1]
References
- ^ a b c d e f g h i j k l m n o Kuhl H (2005). "Pharmacology of estrogens and progestogens: influence of different routes of administration" (PDF). Climacteric. 8 (Suppl 1): 3–63. doi:10.1080/13697130500148875. PMID 16112947. S2CID 24616324.
- ^ Fritz MA, Speroff L (28 March 2012). "Postmenopausal Hormone Therapy". Clinical Gynecologic Endocrinology and Infertility. Lippincott Williams & Wilkins. pp. 751–. ISBN 978-1-4511-4847-3.
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Estrogens | ERTooltip Estrogen receptor 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
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Progonadotropins | |
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Antiestrogens | ERTooltip Estrogen receptor antagonists (incl. SERMsTooltip selective estrogen receptor modulators/SERDsTooltip selective estrogen receptor downregulators) | |
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Aromatase inhibitors | |
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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)
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Others | |
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- See also
- Estrogen receptor modulators
- Androgens and antiandrogens
- Progestogens and antiprogestogens
- List of estrogens
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ERTooltip Estrogen receptor | 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)
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Mixed (SERMsTooltip Selective estrogen receptor modulators) | |
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Antagonists | - Coregulator-binding modulators: ERX-11
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GPERTooltip G protein-coupled estrogen receptor | Agonists | |
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Antagonists | |
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Unknown | |
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- See also
- Receptor/signaling modulators
- Estrogens and antiestrogens
- Androgen receptor modulators
- Progesterone receptor modulators
- List of estrogens
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