Chemical compound
Pharmaceutical compound
17β-Dihydroequilin Clinical data Other names β-Dihydroequilin; Δ7 -17β-Estradiol; 7-Dehydro-17β-estradiol; Estra-1,3,5(10),7-tetraen-3,17β-diol; NSC-12170 Routes of administration By mouth Drug class Estrogen Identifiers (9S ,13S ,14S ,17S )-13-Methyl-6,9,11,12,14,15,16,17-octahydrocyclopenta[a ]phenanthrene-3,17-diol
CAS Number PubChem CID ChemSpider UNII ChEBI ChEMBL CompTox Dashboard (EPA) ECHA InfoCard 100.020.576 Chemical and physical data Formula C 18 H 22 O 2 Molar mass 270.372 g·mol−1 3D model (JSmol ) 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 anaturally occurring estrogen sex hormone found inhorses as well as amedication .[ 1] [ 2] As the C3sulfate ester sodium salt , it is a minor constituent (1.7%) ofconjugated estrogens (CEEs; brand namePremarin ).[ 1] However, asequilin , withequilin sulfate being a major component of CEEs, is transformed into 17β-dihydroequilin in the body, analogously to the conversion ofestrone into estradiol, 17β-dihydroequilin is, along with estradiol, the most important estrogen responsible for the effects of CEEs.[ 1]
17β-Dihydroequilin is an estrogen, or anagonist of theestrogen receptors (ERs), theERα andERβ .[ 1] In terms ofrelative 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 thevagina and 200% of the relative potency of CEEs in theuterus .[ 1] Of theequine estrogens , it shows the highestestrogenic activity and greatest estrogenicpotency .[ 1]
Like CEEs as a whole, 17β-dihydroequilin has disproportionate effects in certaintissues such as theliver anduterus .[ 1] Equilin , the second major component of conjugated estrogens afterestrone , is reversiblytransformed 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 HF Tooltip Hot flashes VE Tooltip Vaginal epithelium UCa Tooltip Urinary calcium FSH Tooltip Follicle-stimulating hormone LH Tooltip Luteinizing hormone HDL Tooltip High-density lipoprotein -C Tooltip Cholesterol SHBG Tooltip Sex hormone-binding globulin CBG Tooltip Corticosteroid-binding globulin AGT Tooltip 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
17β-Dihydroequilin has about 30% of therelative binding affinity oftestosterone forsex hormone-binding globulin (SHBG), relative to 50% forestradiol .[ 1] Themetabolic clearance rate of 17β-dihydroequilin is 1,250 L/day/m2 , relative to 580 L/day/m2 for estradiol.[ 1]
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 anaturally occurring estrane steroid and ananalogue ofestradiol .[ 1] In terms ofchemical structure andpharmacology , equilin (δ7 -estrone) is to 17β-dihydroequilin asestrone is to estradiol.[ 1]
Estrogens
ER Tooltip Estrogen receptor agonistsSteroidal: Alfatradiol Certainandrogens /anabolic steroids (e.g.,testosterone ,testosterone esters ,methyltestosterone ,metandienone ,nandrolone esters ) (via estrogenic metabolites) Certainprogestins (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 Tooltip Estrogen receptor antagonists (incl.SERMs Tooltip selective estrogen receptor modulators /SERDs Tooltip selective estrogen receptor downregulators )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
ER Tooltip 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 andesters ,methyltestosterone ,metandienone (methandrostenolone) ,nandrolone andesters , many others; via estrogenic metabolites)Atrimustine Bolandiol Bolandiol dipropionate Butolame Clomestrone Cloxestradiol Conjugated estriol Conjugated estrogens Cyclodiol Cyclotriol DHEA DHEA-S ent -EstradiolEpiestriol (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 Tooltip Selective estrogen receptor modulators ) Antagonists Coregulator-binding modulators: ERX-11
GPER Tooltip G protein-coupled estrogen receptor
Agonists Antagonists Unknown