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{{Chembox
{{Drugbox|
| Verifiedfields = changed
|IUPAC_name = 17-hydroxy-10,13-dimethyl-1,2,6,7,8,9,11,12,14,15,16,17- dodecahydrocyclopenta[a]phenanthren-3-one
| verifiedrevid = 461094114
| image=Epitestosterone.gif
<!-- Images -->
| width=250
| ImageFile = Epitestosterone.svg
| CAS_number=481-30-1
| ImageSize = 200px
| ATC_prefix=
| ATC_suffix=
| ImageAlt =
<!-- Names -->
| ATC_supplemental=
| IUPACName = 17α-Hydroxyandrost-4-en-3-one
| PubChem=
| SystematicName = (1''R'',3a''S'',3b''R'',9a''R'',9b''S'',11a''S'')-1-Hydroxy-9a,11a-dimethyl-1,2,3,3a,3b,4,5,8,9,9a,9b,10,11,11a-tetradecahydro-7''H''-cyclopenta[''a'']phenanthren-7-one
| DrugBank=
| OtherNames = Isotestosterone; 17α-Testosterone; Androst-4-en-17α-ol-3-one
| chemical_formula = C<sub>19</sub>H<sub>28</sub>O<sub>2</sub>
<!-- Sections -->
| molecular_weight = 288.42
| Section1 = {{Chembox Identifiers
| bioavailability=
| CASNo_Ref = {{cascite|changed|??}}
| metabolism =
| CASNo = 481-30-1
| elimination_half-life=
| ChEBI_Ref = {{ebicite|changed|EBI}}
| excretion =
| ChEBI = 42534
| pregnancy_category =
| ChEMBL_Ref = {{ebicite|correct|EBI}}
| legal_status =
| ChEMBL = 196228
| routes_of_administration=
| ChemSpiderID_Ref = {{chemspidercite|correct|chemspider}}
| melting_point=
| ChemSpiderID = 9789
| specific_rotation=
| DrugBank_Ref = {{drugbankcite|correct|drugbank}}
| sec_combustion=}}
| DrugBank = DB07768
| PubChem = 10204
| StdInChI = 1S/C19H28O2/c1-18-9-7-13(20)11-12(18)3-4-14-15-5-6-17(21)19(15,2)10-8-16(14)18/h11,14-17,21H,3-10H2,1-2H3/t14-,15-,16-,17+,18-,19-/m0/s1
| StdInChIKey = MUMGGOZAMZWBJJ-KZYORJDKSA-N
| SMILES = C[C@]12CC[C@H]3[C@H]([C@@H]1CC[C@H]2O)CCC4=CC(=O)CC[C@]34C
| UNII = 48L726977Z
}}
| Section2 = {{Chembox Properties
| C=19 | H=28 | O=2
| MolarMass = 288.431 g/mol
| Appearance =
| Density =
| MeltingPt =
| BoilingPt =
| Solubility =
}}
| Section3 = {{Chembox Hazards
| MainHazards =
| FlashPt =
| AutoignitionPt =
}}
}}


'''Epitestosterone''', or '''isotestosterone''', also known as '''17α-testosterone''' or as '''androst-4-en-17α-ol-3-one''', is an [[endogenous]] [[steroid]] and an [[epimer]] of the [[androgen]] [[sex hormone]] [[testosterone]]. It is a weak [[competitive antagonist|competitive]] [[receptor antagonist|antagonist]] of the [[androgen receptor]] (AR) and a potent [[5α-reductase inhibitor]].<ref name="Conn2013">{{cite book|author=P. Michael Conn|title=Animal Models for the Study of Human Disease|url=https://books.google.com/books?id=dVLVLIV8rD0C&pg=PA376|date=29 May 2013|publisher=Academic Press|isbn=978-0-12-415912-9|pages=376–}}</ref><ref name="pmid2532272">{{cite journal | vauthors = Stárka L, Bicíková M, Hampl R | title = Epitestosterone--an endogenous antiandrogen? | journal = J. Steroid Biochem. | volume = 33 | issue = 5 | pages = 1019–21 | year = 1989 | pmid = 2532272 | doi = 10.1016/0022-4731(89)90255-0}}</ref>
'''Epitestosterone''' is a natural [[steroid]], an inactive [[isomer]] of the hormone [[testosterone]]. Epitestosterone is believed to form in a similar way to testosterone; however, the exact site of its formation is unknown. It has been shown to accumulate in mammary cyst fluid and in the [[prostate]]. Epitestosterone levels are typically highest in young males; however, by adulthood, most healthy males exhibit a testosterone to epitestosterone ratio (T/E ratio) of about 1:1<ref> {{cite news | url=http://www.asada.gov.au/substances/facts/testosterone.htm | title=Substances: Testosterone to epitestosterone (T/E) ratio | publisher=Australian Government | date=Tuesday, February 28, 2006}}</ref>.


Structurally, epitestosterone differs from testosterone only in the configuration at the hydroxy-bearing carbon, [[:File:Steroid numbering.png|C17]]. Epitestosterone is believed to form in a similar way to testosterone; a 1993 study found that around 50% of epitestosterone production in human males can be ascribed to the testis,<ref name=Dehennin93>{{cite journal |doi=10.1016/0960-0760(93)90025-R |author=Dehennin L |title=Secretion by the human testis of epitestosterone, with its sulfoconjugate and precursor androgen 5-androstene-3 beta,17 α-diol |journal=J. Steroid Biochem. Mol. Biol. |volume=44 |issue=2 |pages=171–7 |date=February 1993 |pmid=8439521 |s2cid=54290658 }}</ref> although the exact pathway of its formation is still the subject of research. It has been shown to accumulate in mammary cyst fluid and in the [[prostate]].<ref name=Dehennin93/> Epitestosterone levels are typically highest in young males; however, by adulthood, most healthy males exhibit a testosterone to epitestosterone ratio (T/E ratio) of about 1:1.<ref>{{cite journal |vauthors=Bellemare V, Faucher F, Breton R, Luu-The V |title=Characterization of 17α-hydroxysteroid dehydrogenase activity (17α-HSD) and its involvement in the biosynthesis of epitestosterone |journal=BMC Biochem. |volume=6|pages=12 |year=2005 |pmid=16018803 |pmc=1185520 |doi=10.1186/1471-2091-6-12 |doi-access=free }}</ref>
==Epistestosterone and Testosterone==


==Society and culture==
It has been shown that [[exogenous]] administration of [[testosterone]] does not affect levels of epitestosterone in the body. As a result, tests to determine the ratio of testosterone to epitestosterone in [[urine]] are used to find athletes who are [[Doping (Sport)|doping]]. A normal healthy person has a ratio of about 1:1 testosterone to epitestosterone (T/E ratio) in their urine .


===Detection of athletic doping===
Although epitestosterone has not been shown to enhance athletic performance, administration of epistestosterone can be used to mask a high level of testosterone if the standard T/E ratio test is used. As such, epitestosterone is banned by many sporting authorities as a masking agent for testosterone.
It has been shown that [[exogenous]] administration of [[testosterone (medication)|testosterone]] does not affect levels of epitestosterone in the body. As a result, tests to determine the ratio of testosterone to epitestosterone in [[urine]] are used to find athletes who are [[Doping (Sport)|doping]].<ref>{{cite journal |vauthors=Aguilera R, Hatton CK, Catlin DH |title=Detection of epitestosterone doping by isotope ratio mass spectrometry |journal=Clin. Chem. |volume=48 |issue=4 |pages=629–36 |year=2002 |doi=10.1093/clinchem/48.4.629 |pmid=11901061 |url=http://www.clinchem.org/cgi/pmidlookup?view=long&pmid=11901061|doi-access=free }}</ref> A study of Australian athletes found that the mean T/E ratio in the study was 1.15:1.<ref>http://doping-info.de/proceedings/proceedings_10_pdf/10_261.pdf {{dead link|date=February 2018}}</ref> Another study found that the max T/E ratio for the 95th percentile of athletes was 3.71:1, and the max T/E ratio for the 99th percentile was 5.25:1.<ref>{{Cite web |url=http://scienceblogs.com/purepedantry/upload/2006/07/te.jpg |title=Archived copy |access-date=2012-04-05 |archive-url=https://web.archive.org/web/20120522063827/http://scienceblogs.com/purepedantry/upload/2006/07/te.jpg |archive-date=2012-05-22 |url-status=dead }}</ref>{{Unreliable source?|date=February 2018}}


Epitestosterone has not been shown to enhance athletic performance, although administration of epistestosterone can be used to mask a high level of testosterone if the standard T/E ratio test is used. As such, epitestosterone is banned by many sporting authorities as a masking agent for testosterone.
In a test, urine taken from [[Floyd Landis]], winner of the [[2006 Tour de France]] showed "an unusual level of testosterone/epitestosterone" of 11:1, in violation of the 4:1 limit imposed by the race organizers. Although this suggested doping, it may have been caused by a low epitestosterone level rather than an artificially elevated testosterone level. Landis has also claimed that an elevated testosterone level could be related to his [[hypothyroidism]].

====Notable cases====
A 1989 report by a committee of the [[Australian Senate]] claimed that "there is hardly a medal winner at the [[1980 Summer Olympics|1980 Moscow Olympics]], certainly not a gold medal winner...who is not on one sort of drug or another: usually several kinds. The Moscow Games might well have been called the Chemists' Games".<ref>{{cite news|url=https://www.economist.com/blogs/graphicdetail/2016/07/daily-chart-15|newspaper=The Economist|title=Doping violations at the Olympics|date=25 July 2016|access-date=June 6, 2017}}</ref> A member of the IOC Medical Commission, Manfred Donike, privately ran additional tests with a new technique for identifying abnormal levels of testosterone by measuring its ratio to epitestosterone in [[urine]]. Twenty percent of the specimens he tested, including those from sixteen gold medalists would have resulted in disciplinary proceedings had the tests been official. The results of Donike's unofficial tests later convinced the IOC to add his new technique to their testing protocols.<ref name="D. Derse2001">{{cite book|first1=Wayne (Ph.D.)|last1=Wilson|first2=Ed|last2=Derse|title=Doping in Élite Sport: The Politics of Drugs in the Olympic Movement|url=https://archive.org/details/dopinginelitespo00wils|url-access=registration|access-date=19 July 2012|year=2001|publisher=Human Kinetics|isbn=978-0-7360-0329-2|pages=[https://archive.org/details/dopinginelitespo00wils/page/77 77]–}}</ref><ref name="Sytkowski2006">{{cite book|first=Arthur J.|last= Sytkowski|title=Erythropoietin: Blood, Brain and Beyond|url=https://books.google.com/books?id=v135CsEL_LQC&pg=PA187|access-date=19 July 2012|date=May 2006|publisher=John Wiley & Sons|isbn=978-3-527-60543-9|pages=187–}}</ref>


In 1996 the US athlete [[Mary Decker]] failed a T/E test with a T/E ratio of greater than 6, the limit in force at the time. She took the case to arbitration, arguing that birth control pills can cause [[false positive]]s for the test, but the arbitration panel ruled against her.
In 1996 the US athlete [[Mary Decker]] failed a T/E test with a T/E ratio of greater than 6, the limit in force at the time. She took the case to arbitration, arguing that birth control pills can cause [[false positive]]s for the test, but the arbitration panel ruled against her.


On September 20, 2007 [[Floyd Landis]] was stripped of his title as winner of the [[2006 Tour de France|Tour de France]], and was subjected to a two-year ban from professional racing after a second test showing an elevated T/E ratio. Landis won the 17th stage of the tour; however, tests taken immediately after the stage victory showed a T/E ratio of 11:1, more than double the 4:1 imposed limit (recently lowered from prior limits of 8:1 and 6:1). On August 1, 2006, media reports said that [[Organic synthesis|synthetic]] testosterone had been detected in the A sample, using the carbon [[isotope]] ratio test [[Isotope-ratio mass spectrometry|CIR]]. The presence of synthetic testosterone means that some of the testosterone in Landis's body came from an external source and was not naturally produced by his own system. These results conflict with Landis's public speculation that it was a natural occurrence.<ref>{{cite news|url=http://www.wfaa.com/sharedcontent/dws/wfaa/latestnews/stories/wfaa060731_mo_landis.ae9233.html |title=Synthetic testosterone found in Landis urine sample |publisher=Associated Press |date=2006-07-31 |access-date=2007-09-25 |archive-url=https://web.archive.org/web/20071212001400/http://www.wfaa.com/sharedcontent/dws/wfaa/latestnews/stories/wfaa060731_mo_landis.ae9233.html |archive-date=2007-12-12 |url-status=dead }}</ref> Landis originally denied the charges, but in 2010 Landis admitted to doping during much of his career,<ref name="doping-wsj">{{Cite news|url=https://www.wsj.com/articles/SB10001424052748703691804575255410855321120|title=Cyclist Floyd Landis Admits Doping, Alleges Use by Armstrong and Others| publisher=The Wall Street Journal| date=2010-05-20 | access-date=2010-05-20 | first=Reed | last=Albergotti}}</ref> but continued to adamantly deny taking testosterone that would have led to the positive test in the 2006 Tour de France.<ref name="doping-espn">{{Cite web|url=https://www.espn.com/olympics/cycling/news/story?id=5203604|title=Landis admits doping, accuses Lance|author=Bonnie D. Ford|publisher=[[ESPN]]|date=2010-05-20}}</ref>
== External links ==

* [http://www.nytimes.com/2006/07/27/sports/othersports/27cnd-doping.html?ei=5094&en=f616263b07608f96&hp=&ex=1154059200&adxnnl=1&partner=homepage&adxnnlx=1154019757-CjNJWUKLfj1Nxefcjj2ehQ Landis Fails Drug Test After Triumph in Tour de France]

* [http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?cmd=Retrieve&db=PubMed&list_uids=14630088&dopt=Abstract Institute of Endocrinology Abstract on Epistestosterone]

== Notes ==

<!--<nowiki>

* See http://en.wikipedia.org/wiki/Wikipedia:Footnotes for an explanation of how to generate footnotes using the <ref> and </ref> tags and the template below.


==See also==
</nowiki>-->
* [[17α-Estradiol]] (epiestradiol)


==References==
<div class="references-small">
{{Reflist|2}}


==External links==
{{FootnotesSmall|resize={{{1|100%}}}}}
* [http://news.bbc.co.uk/sport2/hi/other_sports/cycling/5237990.stm Landis has T/E ratio twice the tour limit]
* {{cite journal |doi=10.1016/S0960-0760(03)00383-2 |author=Stárka L |title=Epitestosterone |journal=J. Steroid Biochem. Mol. Biol. |volume=87 |issue=1 |pages=27–34 |date=October 2003 |pmid=14630088 |s2cid=208789812 }}
* {{cite journal |doi=10.1136/bmj.4.5732.406 |vauthors=Loraine JA, Ismail AA, Adamopoulos DA, Dove GA |title=Endocrine Function in Male and Female Homosexuals |journal=Br Med J |volume=4 |issue=5732 |pages=406–9 |date=November 1970 |pmid=5481520 |pmc=1819981 }}
* {{cite journal |doi=10.1677/joe.0.0630549 |vauthors=Griffiths PD, Merry J, Browning MC |title=Homosexual women: an endocrine and psychological study |journal=J. Endocrinol. |volume=63 |issue=3 |pages=549–56 |date=December 1974 |pmid=4452820 |url=http://joe.endocrinology-journals.org/cgi/pmidlookup?view=long&pmid=4452820|display-authors=etal}}


{{Steroid hormones}}
</div>
{{Androgen receptor modulators}}


[[Category:5α-Reductase inhibitors]]
[[da: Epitestosteron]]
[[Category:Androstanes]]
[[Category:Steroidal antiandrogens]]
[[Category:World Anti-Doping Agency prohibited substances]]

Latest revision as of 18:33, 21 July 2024

Epitestosterone
Names
IUPAC name
17α-Hydroxyandrost-4-en-3-one
Systematic IUPAC name
(1R,3aS,3bR,9aR,9bS,11aS)-1-Hydroxy-9a,11a-dimethyl-1,2,3,3a,3b,4,5,8,9,9a,9b,10,11,11a-tetradecahydro-7H-cyclopenta[a]phenanthren-7-one
Other names
Isotestosterone; 17α-Testosterone; Androst-4-en-17α-ol-3-one
Identifiers
3D model (JSmol)
ChEBI
ChEMBL
ChemSpider
DrugBank
ECHA InfoCard 100.169.813 Edit this at Wikidata
UNII
  • InChI=1S/C19H28O2/c1-18-9-7-13(20)11-12(18)3-4-14-15-5-6-17(21)19(15,2)10-8-16(14)18/h11,14-17,21H,3-10H2,1-2H3/t14-,15-,16-,17+,18-,19-/m0/s1
    Key: MUMGGOZAMZWBJJ-KZYORJDKSA-N
  • C[C@]12CC[C@H]3[C@H]([C@@H]1CC[C@H]2O)CCC4=CC(=O)CC[C@]34C
Properties
C19H28O2
Molar mass 288.431 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
☒N verify (what is checkY☒N ?)

Epitestosterone, or isotestosterone, also known as 17α-testosterone or as androst-4-en-17α-ol-3-one, is an endogenous steroid and an epimer of the androgen sex hormone testosterone. It is a weak competitive antagonist of the androgen receptor (AR) and a potent 5α-reductase inhibitor.[1][2]

Structurally, epitestosterone differs from testosterone only in the configuration at the hydroxy-bearing carbon, C17. Epitestosterone is believed to form in a similar way to testosterone; a 1993 study found that around 50% of epitestosterone production in human males can be ascribed to the testis,[3] although the exact pathway of its formation is still the subject of research. It has been shown to accumulate in mammary cyst fluid and in the prostate.[3] Epitestosterone levels are typically highest in young males; however, by adulthood, most healthy males exhibit a testosterone to epitestosterone ratio (T/E ratio) of about 1:1.[4]

Society and culture

[edit]

Detection of athletic doping

[edit]

It has been shown that exogenous administration of testosterone does not affect levels of epitestosterone in the body. As a result, tests to determine the ratio of testosterone to epitestosterone in urine are used to find athletes who are doping.[5] A study of Australian athletes found that the mean T/E ratio in the study was 1.15:1.[6] Another study found that the max T/E ratio for the 95th percentile of athletes was 3.71:1, and the max T/E ratio for the 99th percentile was 5.25:1.[7][unreliable source?]

Epitestosterone has not been shown to enhance athletic performance, although administration of epistestosterone can be used to mask a high level of testosterone if the standard T/E ratio test is used. As such, epitestosterone is banned by many sporting authorities as a masking agent for testosterone.

Notable cases

[edit]

A 1989 report by a committee of the Australian Senate claimed that "there is hardly a medal winner at the 1980 Moscow Olympics, certainly not a gold medal winner...who is not on one sort of drug or another: usually several kinds. The Moscow Games might well have been called the Chemists' Games".[8] A member of the IOC Medical Commission, Manfred Donike, privately ran additional tests with a new technique for identifying abnormal levels of testosterone by measuring its ratio to epitestosterone in urine. Twenty percent of the specimens he tested, including those from sixteen gold medalists would have resulted in disciplinary proceedings had the tests been official. The results of Donike's unofficial tests later convinced the IOC to add his new technique to their testing protocols.[9][10]

In 1996 the US athlete Mary Decker failed a T/E test with a T/E ratio of greater than 6, the limit in force at the time. She took the case to arbitration, arguing that birth control pills can cause false positives for the test, but the arbitration panel ruled against her.

On September 20, 2007 Floyd Landis was stripped of his title as winner of the Tour de France, and was subjected to a two-year ban from professional racing after a second test showing an elevated T/E ratio. Landis won the 17th stage of the tour; however, tests taken immediately after the stage victory showed a T/E ratio of 11:1, more than double the 4:1 imposed limit (recently lowered from prior limits of 8:1 and 6:1). On August 1, 2006, media reports said that synthetic testosterone had been detected in the A sample, using the carbon isotope ratio test CIR. The presence of synthetic testosterone means that some of the testosterone in Landis's body came from an external source and was not naturally produced by his own system. These results conflict with Landis's public speculation that it was a natural occurrence.[11] Landis originally denied the charges, but in 2010 Landis admitted to doping during much of his career,[12] but continued to adamantly deny taking testosterone that would have led to the positive test in the 2006 Tour de France.[13]

See also

[edit]

References

[edit]
  1. ^ P. Michael Conn (29 May 2013). Animal Models for the Study of Human Disease. Academic Press. pp. 376–. ISBN 978-0-12-415912-9.
  2. ^ Stárka L, Bicíková M, Hampl R (1989). "Epitestosterone--an endogenous antiandrogen?". J. Steroid Biochem. 33 (5): 1019–21. doi:10.1016/0022-4731(89)90255-0. PMID 2532272.
  3. ^ a b Dehennin L (February 1993). "Secretion by the human testis of epitestosterone, with its sulfoconjugate and precursor androgen 5-androstene-3 beta,17 α-diol". J. Steroid Biochem. Mol. Biol. 44 (2): 171–7. doi:10.1016/0960-0760(93)90025-R. PMID 8439521. S2CID 54290658.
  4. ^ Bellemare V, Faucher F, Breton R, Luu-The V (2005). "Characterization of 17α-hydroxysteroid dehydrogenase activity (17α-HSD) and its involvement in the biosynthesis of epitestosterone". BMC Biochem. 6: 12. doi:10.1186/1471-2091-6-12. PMC 1185520. PMID 16018803.
  5. ^ Aguilera R, Hatton CK, Catlin DH (2002). "Detection of epitestosterone doping by isotope ratio mass spectrometry". Clin. Chem. 48 (4): 629–36. doi:10.1093/clinchem/48.4.629. PMID 11901061.
  6. ^ http://doping-info.de/proceedings/proceedings_10_pdf/10_261.pdf [dead link‍]
  7. ^ "Archived copy". Archived from the original on 2012-05-22. Retrieved 2012-04-05.{{cite web}}: CS1 maint: archived copy as title (link)
  8. ^ "Doping violations at the Olympics". The Economist. 25 July 2016. Retrieved June 6, 2017.
  9. ^ Wilson, Wayne (Ph.D.); Derse, Ed (2001). Doping in Élite Sport: The Politics of Drugs in the Olympic Movement. Human Kinetics. pp. 77–. ISBN 978-0-7360-0329-2. Retrieved 19 July 2012.
  10. ^ Sytkowski, Arthur J. (May 2006). Erythropoietin: Blood, Brain and Beyond. John Wiley & Sons. pp. 187–. ISBN 978-3-527-60543-9. Retrieved 19 July 2012.
  11. ^ "Synthetic testosterone found in Landis urine sample". Associated Press. 2006-07-31. Archived from the original on 2007-12-12. Retrieved 2007-09-25.
  12. ^ Albergotti, Reed (2010-05-20). "Cyclist Floyd Landis Admits Doping, Alleges Use by Armstrong and Others". The Wall Street Journal. Retrieved 2010-05-20.
  13. ^ Bonnie D. Ford (2010-05-20). "Landis admits doping, accuses Lance". ESPN.
[edit]
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