Estrone was first discovered in 1929, and was introduced for medical use shortly thereafter.[13][14][15] Although it has been used clinically in the past, estrone has largely been discontinued and is mostly no longer marketed.[9][16]
Estrone has been used by intramuscular injection at a dosage of 0.1 to 2 mg per week, or 0.1 to 0.5 mg given 2 or 3 times per week, for the treatment of menopausal symptoms such as hot flashes and vaginal atrophy,[20][21] and at a dosage of 0.1 to 1.0 mg weekly in single or divided doses for the treatment of female hypogonadism, surgical castration, and primary ovarian failure.[22] The range of single doses of estrone by intramuscular injection that are typically used clinically in women is 0.1 to 5 mg.[23] High doses of intramuscular estrone have been used for prostate cancer in men and for breast cancer in women.[17][18]
Although estrone by intramuscular injection was originally formulated as an oil solution, it was soon replaced by formulations of estrone as an aqueous suspension due to a longer duration of action of these formulations.[36][37][27][18][38][39][40]
Side effects
Side effects of estrogens like estrone include breast tenderness, breast enlargement, headache, nausea, fluid retention, and edema, among others.[5] It can also cause endometrial hyperplasia.[41][42][43]
Pharmacology
Pharmacodynamics
Mechanism of action
Estrone is an estrogen, specifically an agonist of the estrogen receptors (ERs) ERα and ERβ.[5][44] It is a far less potent estrogen than is estradiol, and as such is a relatively weak estrogen.[5][44] Given by subcutaneous injection in mice, estradiol is about 10-fold more potent than estrone and about 100-fold more potent than estriol.[45] According to one study, the relative binding affinities of estrone for the human ERα and ERβ were 4.0% and 3.5% of those estradiol, respectively, and the relative transactivational capacities of estrone at the ERα and ERβ were 2.6% and 4.3% of those of estradiol, respectively.[44] In accordance, the estrogenic activity of estrone has been reported to be approximately 4% of that of estradiol.[5] Other studies have reported that estrone has about one-tenth of the potency of estradiol in activating the ERs in vitro.[46][47][48] Because estrone can be transformed into estradiol, which is far more potent as an estrogen in comparison, most or all of the estrogenic potency of estrone in vivo is actually due to conversion into estradiol.[5][12] As such, similarly to the case of estrone sulfate, estrone is considered to be a prodrug of estradiol.[5][49] Some in vitro research has suggested that estrone might be able to partiallyantagonize the actions of estradiol,[50][51][52] but this does not appear to be of clinical significance.[5][53][54][55] In contrast to estradiol and estriol, estrone is not a ligand of the G protein-coupled estrogen receptor (affinity >10,000 nM).[56]
Effects in the body and brain
In clinical research in the 1930s, estrone was given via intramuscular injection to ovariectomized women in order to study its effects and to elucidate the biological properties of estrogens in humans.[41][42][43] In these studies, prior to administration of estrone, amenorrhea, atrophy of the breasts (as well as flaccidity and small and non-erectile nipples), vagina, and endometrium, vaginal dryness, and subjective symptoms of ovariectomy (e.g., hot flashes, mood changes) were all present in the women.[41][42][43] Treatment with estrone was found to dose- and time-dependently produce a variety of effects, including breast changes, reproductive tract changes of the vagina, cervix, and endometrium/uterus, and relief from the subjective symptoms of ovariectomy, as well as increased libido.[41][42][43] Breast changes specifically included enlargement and a sense of fullness, increased sensitivity and pigmentation of the nipples as well as nipple erection, tingling within the breast mammary glandular tissue, and aching and soreness of the breasts.[41][42][43] Reproductive tract changes included increased growth, thickness, and differentiation of the endometrium, and reversal of vaginal and cervical atrophy, which were accompanied by increased congestion of the cervix and mucous discharge from the cervix, uterine cramps and needle-like pains, pelvic fullness, a "bearing-down" sensation, and increased vaginal lubrication, as well as uterine bleeding both during treatment and in the days following cessation of injections.[41][42][43] Endometrial hyperplasia also occurred with sufficiently high doses of estrone.[41][42][43]
Clinical research has confirmed the nature of estrone as an inactive prodrug of estradiol.[5][53][54][55] With oral administration of estradiol, the ratio of estradiol levels to estrone levels is about 5 times higher on average than under normal physiological circumstances in premenopausal women and with parenteral (non-oral) routes of estradiol.[5] Oral administration of menopausal replacement dosages of estradiol results in low, follicular phase levels of estradiol, whereas estrone levels resemble the high levels seen during the first trimester of pregnancy.[5][57][58] In spite of markedly elevated levels of estrone with oral estradiol but not with transdermal estradiol, clinical studies have shown that doses of oral and transdermal estradiol achieving similar levels of estradiol possess equivalent and non-significantly different potency in terms of measures including suppression of luteinizing hormone and follicle-stimulating hormone levels, inhibition of bone resorption, and relief of menopausal symptoms such as hot flashes.[5][53][54][55][59] In addition, estradiol levels were found to correlate with these effects, while estrone levels did not.[53][54] These findings confirm that estrone has very low estrogenic activity, and also indicate that estrone does not diminish the estrogenic activity of estradiol.[5][53][54][55] This contradicts some cell-freein-vitro research suggesting that high concentrations of estrone might be able to partiallyantagonize the actions of estradiol.[50][51][52]
v·d·ePotencies and durations of natural estrogens by intramuscular injection
Estrone in oil solution by intramuscular injection has a shorter duration than estrone in aqueous suspension by intramuscular injection.[36] Estrone in oil solution by intramuscular injection is rapidly absorbed, while estrone in aqueous suspension has a prolonged period of absorption.[62] Upon intramuscular injection of estrone in aqueous solution, the water from the preparation is absorbed and a microcrystalline depot of estrone that is slowly absorbed by the body is formed.[37] This is responsible for the prolonged duration of estrone in aqueous suspension compared to oil solution.[36][37]
Distribution
Unlike estradiol and estriol, estrone is not accumulated in target tissues.[5][63] In terms of plasma protein binding, estrone is bound approximately 16% to sex hormone-binding globulin (SHBG) and 80% to albumin,[5] with the remainder (2.0 to 4.0%) circulating free or unbound.[7] Estrone has about 24% of the relative binding affinity of estradiol for SHBG, and hence is relatively poorly bound to SHBG.[5][11]
This diagram illustrates the metabolic pathways involved in the metabolism of estrogens (i.e., estradiol, estrone, and estriol) in humans.
Estrone is conjugated into estrogen conjugates such as estrone sulfate and estrone glucuronide by sulfotransferases and glucuronidases, and can also be hydroxylated by cytochrome P450 enzymes into catechol estrogens such as 2-hydroxyestrone and 4-hydroxyestrone or into estriol.[5] Both of these transformations take place predominantly in the liver.[5] Estrone can also be reversibly converted into estradiol by 17β-hydroxysteroid dehydrogenases (17β-HSDs), and this accounts for most or all of its estrogenic activity.[5][12] 17β-HSD isoforms that are involved in the conversion of estrone into estradiol include 17β-HSD1, 17β-HSD3, 17β-HSD4, 17β-HSD7, 17β-HSD8, and 17β-HSD12, although the relative contributions of the different isoforms is unknown.[67][additional citation(s) needed]
The biological half-lives of estrone and estradiol in the circulation are both about 10 to 70 minutes, whereas the biological half-life of estrone sulfate in the circulation is about 10 to 12 hours.[5][68][69] The metabolic clearance rate of estrone is 1,050 L/day/m2 and of estradiol is 580 L/day/m2, while that of estrone sulfate is 80 L/day/m2.[5] For comparison, the metabolic clearance rate of estriol is 1,110 L/day/m2.[5] A single 1 to 2 mg dose of estrone in oil solution by intramuscular injection has a duration of about 2 or 3 days.[45][70][71] As an aqueous suspension by intramuscular injection, estrone was used at a dose of 0.1 to 0.5 mg 2 to 3 times per week, or at a dose of 0.1 to 2 mg once a week or in divided doses.[72] In one rodent study, exogenous estrone was administered and increased circulating estradiol levels by about 10-fold; co-administration of a selective 17β-HSD1 inhibitor decreased estradiol levels by about 50%.[73]
The ratio of circulating estrone to circulating estradiol is the same at about 5:1 with both oral estradiol and oral estrone sulfate.[5] An investigational estrone vaginal ring was found to result in a ratio of estrone to estradiol of 4:1 or 5:1 initially, but this decreased to about 1:1 with continuous therapy.[74]
In 1927, Bernhard Zondek and Selmar Aschheim discovered that large amounts of estrogens were excreted in the urine of pregnant women.[75][76] This rich source of estrogens allowed the development of potent estrogenic formulations for scientific and clinical use.[76][13] In 1929, pure crystalline estrone was isolated from the urine of pregnant women by various researchers.[13][77] By 1929, pharmaceutical preparations including Amniotin (Squibb), Progynon (Schering), and Theelin (Parke-Davis), purified from pregnancy urine, placentas, and/or amniotic fluid and containing purified estrone or mixtures of estrogens that included estrone, were being sold commercially for use by intramuscular injection.[78][13][14][79][15][80] Other products and brand names of estrone marketed in the 1930s included Estrone (Abbott, Lilly), Oestroform (British Drug Houses), Folliculin (Organon), Menformon (Organon), and Ketodestrin (Paines & Byrne), among others.[14][79][80][81] These formulations included ampoules of oil or aqueous solution for intramuscular injection, oraltablets, and vaginal suppositories.[80][14][23][82] Estrone in aqueous suspension for use by intramuscular injection was first described in 1941 and was introduced for medical use under the brand name Theelin Aqueous Suspension by 1944.[36][23][83]
Society and culture
Generic names
Estrone is the generic name of estrone in American English and its INN, USP, BAN, DCF, DCIT, and JAN.[8][9][10][16]Oestrone, in which the "O" is silent, was the former BAN of estrone and its name in British English,[8][10][9] but the spelling was eventually changed to estrone.[16]
Brand names
Estrone has been marketed under a variety of brand names, including Andrestraq, Aquacrine, A.T.V., Bestrone, Centrogen, Cicatral, Cormone, Crinovaryl, Cristallovar, Crystogen, Destrone, Disynformon, Endofolliculina, Estragyn, Estroject, Estrol, Estrone, Estrone Aqueous Suspension, Estrone-A, Estrugenone, Estrusol, Femestrone, Femidyn, Folikrin, Folipex, Folisan, Folliculin, Follicunodis, Follidrin, Gineburno, Glandubolin, Grietalgen, Grietalgen Hidrocort, Gynogen, Hiestrone, Hormofollin, Hormonin, Hormovarine, Kestrin, Kestrone, Ketodestrin, Kolpon, Ladies Pearl, Livifolin, Menagen, Metharmon-F, Neo-Estrone, Oestrilin, Oestrin, Oestroform, Oestroperos, Ovex, Ovifollin, Perlatan, Progynon, Senikolp, Solliculin, Solutio Folliculinum, Synergon (in combination with progesterone), Theelin, Thynestron, Tokokin, Unden, Unigen, Wehgen, and Wynestron.[8][10][9][1][16][84][85]
Brand names of estrone in aqueous suspension specifically include Bestrone, Estaqua, Estrofol, Estroject, Estrone-A, Estronol, Femogen, Foygen Aqueous, Gravigen Aqueous, Gynogen, Hormogen-A, Kestrin Aqueous, Kestrone, Theelin Aqueous, Theogen, Unigen, and Wehgen.[86]
Availability
Although estrone has been widely marketed in the past, it has mostly been discontinued and remains available in only a few countries.[9][16] These countries reportedly include Canada , Georgia, Monaco, and Taiwan.[16] However, estrone remains widely available throughout the world in the form of estrone sulfate, which can be found in estropipate (piperazine estrone sulfate), conjugated estrogens (Premarin), and esterified estrogens (Estratab, Menest).[9][87]
↑ 13.013.113.213.3Science In The Bedroom: A History Of Sex Research. Basic Books. 19 May 1995. pp. 128–. ISBN978-0-465-07259-0. https://books.google.com/books?id=Z7__qJK470AC&pg=PA128. "When Allen and Doisy heard about the [Ascheim-Zondek test for the diagnosis of pregnancy], they realized there was a rich and easily handled source of hormones in urine from which they could develop a potent extract. [...] Allen and Doisy's research was sponsored by the committee, while that of their main rival, Adolt Butenandt (b. 1903) of the University of Gottingen was sponsored by a German pharmaceutical firm. In 1929, both terms announced the isolation of a pure crystal female sex hormone, estrone, in 1929, although Doisy and Allen did so two months earlier than Butenandt.27 By 1931, estrone was being commercially produced by Parke Davis in this country, and Schering-Kahlbaum in Germany. Interestingly, when Butenandt (who shared the Nobel Prize for chemistry in 1939) isolated estrone and analyzed its structure, he found that it was a steroid, the first hormone to be classed in this molecular family."[yes|permanent dead link|dead link}}]
↑"Sex hormones and their modulators". Martindale: The Complete Drug Reference (36th ed.). London: Pharmaceutical Press. 2009. pp. 2101, 2127. ISBN978-0-85369-840-1. "Estrone [...] Progesterone [...] Multi-ingredient: [...] Fr.: Synergon [...] Turk.: Synergon"
↑"Knowledge, practices, and attitudes regarding emergency contraception among students at a university in Ghana". Int J Gynaecol Obstet105 (3): 206–9. June 2009. doi:10.1016/j.ijgo.2009.01.008. PMID19232600. "Synergon, a combination of progesterone and oestrone in an injectable form, is marketed to induce withdrawal bleeding in women with nongravid amenorrhea; however, it can be used as an arbortifacient [11].".
↑"Relative duration of action of natural and synthetic estrogens administered parenterally in women with estrogen deficiency". The Journal of Clinical Endocrinology and Metabolism12 (1): 28–35. January 1952. doi:10.1210/jcem-12-1-28. PMID14907837.
↑"Comparison of chemical-induced transcriptional activation of fish and human estrogen receptors: regulatory implications". Toxicol. Lett.201 (2): 152–75. March 2011. doi:10.1016/j.toxlet.2010.12.020. PMID21195753.
↑ 53.053.153.253.353.4"Comparison of the effects of oral and transdermal oestradiol administration on oestrogen metabolism, protein synthesis, gonadotrophin release, bone turnover and climacteric symptoms in postmenopausal women". Clin. Endocrinol. (Oxf)30 (3): 241–9. March 1989. doi:10.1111/j.1365-2265.1989.tb02232.x. PMID2512035.
↑ 54.054.154.254.354.4"Pharmacokinetics and pharmacodynamics of transdermal dosage forms of 17 beta-estradiol: comparison with conventional oral estrogens used for hormone replacement". Am. J. Obstet. Gynecol.152 (8): 1099–106. August 1985. doi:10.1016/0002-9378(85)90569-1. PMID2992279.
↑ 55.055.155.255.3"Oestrogens, gonadotrophins and SHBG during oral and cutaneous administration of oestradiol-17 beta to menopausal women". Acta Endocrinol.101 (4): 592–6. December 1982. doi:10.1530/acta.0.1010592. PMID6818806.
↑"Hormone replacement with estradiol: conventional oral doses result in excessive exposure to estrone". Altern Med Rev10 (1): 36–41. March 2005. PMID15771561.
↑"Biological effects of estradiol-17 beta in postmenopausal women: oral versus percutaneous administration". J. Clin. Endocrinol. Metab.62 (3): 536–41. March 1986. doi:10.1210/jcem-62-3-536. PMID3080464.
↑"The oestrogens". Br Med J1 (5128): 1029–31. April 1959. doi:10.1136/bmj.1.5128.1029. PMID13638626. "Oestrone is weakly active by mouth, its potency (see Table) being approximately 1/25th that of stilboestrol (25 mg E1 = 1 mg DES = 2.5 mg CEEs = 0.05 mg EE).".
↑"Management of the Menopause". The Permanente Journal2 (3): 25–29. Summer 1998. doi:10.7812/TPP/98.930. http://www.thepermanentejournal.org/files/PDF/Summer1998.pdf#page=27. "Using the same principle of delayed absorption, however, we have been able to improve the efficiency of estrone by suspending this fat soluble substance in an aqueous medium, reversing the procedure of suspending water soluble substances such as penicillin. in oil.3 The action of estrone in suspension is prolonged because the water vehicle is rapidly absorbed leaving a deposit of crystals in the tissues thus behaving like small implants of crystals which we know are relatively long acting.".
↑"In vivo uptake and subcellular distribution of tritium-labeled estrogens in human endometrium, myometrium, and vagina". J. Clin. Endocrinol. Metab.56 (1): 76–86. January 1983. doi:10.1210/jcem-56-1-76. PMID6847874.
↑"Pharmacology of estrogens and progestogens: influence of different routes of administration". Climacteric : the Journal of the International Menopause Society8 Suppl 1: 3–63. August 2005. doi:10.1080/13697130500148875. PMID16112947.
↑"The relationship between urinary oestrogens and oestrogens produced in the body". The Journal of Endocrinology16 (2): 202–212. December 1957. doi:10.1677/joe.0.0160202. PMID13491750.
↑"Excretion of estrogen metabolites by humans. I. The fate of small doses of estrone and estradiol-17beta". The Journal of Biological Chemistry214 (1): 335–349. May 1955. doi:10.1016/S0021-9258(18)70972-1. PMID14367392.
↑Micromedex (1 January 2003). USP DI 2003: Drug Information for Healthcare Professionals. Thomson Micromedex. p. 1246. ISBN978-1-56363-429-1. https://books.google.com/books?id=zEzWtsVl-KgC. "ESTRONE Parenteral Dosage Forms ESTRONE INJECTABLE SUSPENSION USP Usual adult dose Atrophic vaginitis or Menopausal (vasomotor) symptoms or Vulvar atrophy—Intramuscular, 100 to 500 mcg (0.1 to 0.5 mg) two or three times a week, cyclically or continuously as appropriate. Estrogen deficiency, due to ovariectomy or Female hypogonadism or Primary ovarian failure—Intramuscular, 100 mcg (0.1 mg) to 1 mg a week, administered as a single dose or in divided doses, cyclically or continuously. A few patients may need doses of up to 2 mg a week."
↑"17beta-hydroxysteroid dehydrogenase Type 1, and not Type 12, is a target for endocrine therapy of hormone-dependent breast cancer". International Journal of Cancer122 (9): 1931–1940. May 2008. doi:10.1002/ijc.23350. PMID18183589.
↑"Diethylstilbestrol in aqueous suspension". The Journal of Clinical Endocrinology and Metabolism6 (6): 420–422. June 1946. doi:10.1210/jcem-6-6-420. PMID20988414. "We have already reported our employing injections of estrone crystals suspended in aqueous medium in order to obtain freedom from allergic reactions (1). This preparation, now available commercially, has proven satisfactory not only from this standpoint, but also because of its increased effectiveness over estrone dissolved in oil.".