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Melengestrol acetate

Not to be confused with Megestrol acetate.
Melengestrol acetate
Clinical data
Trade namesHeifermax, MGA
Other namesMGA; MLA; MLGA; Melengesterol acetate; Methylsuperlutin; U-21240; BDH-1921; 17α-Acetoxy-16-methylene-6-methyl-6-dehydroprogesterone; 17α-Acetoxy-16-methylene-6-methylpregna-4,6-diene-3,20-dione
Drug classProgestogen; Progestin; Progestogen ester
ATC code
  • None
Identifiers
  • [(8R,9S,10R,13S,14S,17R)-17-acetyl-6,10,13-trimethyl-16-methylidene-3-oxo-1,2,8,9,11,12,14,15-octahydrocyclopenta[a]phenanthren-17-yl] acetate
CAS Number
PubChem CID
DrugBank
ChemSpider
UNII
KEGG
CompTox Dashboard (EPA)
ECHA InfoCard100.018.964 Edit this at Wikidata
Chemical and physical data
FormulaC25H32O4
Molar mass396.527 g·mol−1
3D model (JSmol)
  • O=C4\C=C3\C(=C/[C@@H]1[C@H](CC[C@@]2([C@](OC(=O)C)(C(=C)\C[C@@H]12)C(=O)C)C)[C@@]3(C)CC4)C
  • InChI=1S/C25H32O4/c1-14-11-19-20(23(5)9-7-18(28)13-21(14)23)8-10-24(6)22(19)12-15(2)25(24,16(3)26)29-17(4)27/h11,13,19-20,22H,2,7-10,12H2,1,3-6H3/t19-,20+,22+,23-,24+,25+/m1/s1
  • Key:UDKABVSQKJNZBH-DWNQPYOZSA-N

Melengestrol acetate (MLGA), sold under the brand names Heifermax and MGA among others, is a progestin medication which is used in animal reproduction.[1][2] It is not approved for use in humans, and is instead used as an implantable contraceptive for captive animals in zoos and other refuges,[3] and is also used as a feed additive to promote growth in cattle, a purpose it is licensed for in the United States and Canada.[4]

Uses

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Animal reproduction

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MLGA is used in animal reproduction.[3][4]

Pharmacology

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Pharmacodynamics

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MLGA is a progestogen, and hence is an agonist of the progesterone receptor.[5] It has been found to possess 73% of the affinity of progesterone for the progesterone receptor in rhesus monkey uterus.[5]

Chemistry

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See also: List of progestogens, Progestogen ester, and List of progestogen esters

MLGA, also known as 17α-acetoxy-16-methylene-6-dehydro-6-methylprogesterone or as 17α-acetoxy-16-methylene-6-methylpregna-4,6-diene-3,20-dione, is a synthetic pregnane steroid and a derivative of progesterone.[1][2] It is specifically a derivative of 17α-hydroxyprogesterone with a methyl group at the C6 position, a methylene group at the C16 position, a double bond between the C6 and C7 positions, and an acetate ester at the C17α position.[1][2] As such, it is also a derivative of 16-methylene-17α-hydroxyprogesterone acetate. MLGA is the acetate ester of melengestrol, which in contrast, has never been marketed.[1] Analogues of MLGA include other 17α-hydroxyprogesterone derivatives such as chlormadinone acetate, chlormethenmadinone acetate, cyproterone acetate, delmadinone acetate, hydroxyprogesterone caproate, medroxyprogesterone acetate, megestrol acetate, methenmadinone acetate, and osaterone acetate.[1] The only structural difference between MLGA and megestrol acetate is the presence of the C16 methylene group in the former.[1]

Society and culture

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In November 2024, the FDA approved melengestrol acetate Type A liquid medicated article (brand name MEL 500) for increased rate of weight gain, improved feed efficiency and suppression of estrus (heat) in heifers fed in confinement for slaughter; and for suppression of estrus (heat) in heifers intended for breeding.[6][7]

Generic names

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Melengestrol acetate is the generic name of the drug and its USANTooltip United States Adopted Name and USPTooltip United States Pharmacopeia.[1][2] Melengestrol is the INNTooltip International Nonproprietary Name and BANTooltip British Approved Name of the unesterified free alcohol form.[1][2]

Brand names

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MLGA is marketed under the brand names Heifermax and MGA among others.[1][2]

References

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  1. ^ a b c d e f g h i Elks J (14 November 2014). The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies. Springer. pp. 764–. ISBN 978-1-4757-2085-3.
  2. ^ a b c d e f "Melengestrol". Drugs.com. Archived from the original on 30 July 2017.
  3. ^ a b Asa CS, Porton IJ (2010). "Chapter 34: Contraception as a Management Tool for Controlling Surplus Animals". In Kleiman DG, Thompson KV, Baer CK (eds.). Wild Mammals in Captivity: Principles and Techniques for Zoo Management (2nd ed.). Chicago, IL: University of Chicago Press. pp. 469–482. ISBN 9780226440118. Retrieved 17 March 2016.
  4. ^ a b Sharman M, van Ginkel L, MacNeil JD (26 November 2009). "Chapter 4: Current Analytical Methods Used for the Detection of Hormone Residues". In Kay JF (ed.). Analyses for Hormonal Substances in Food-Producing Animals. Royal Society of Chemistry. p. 139. doi:10.1039/9781849730723-00129. ISBN 978-0-85404-198-5. Retrieved 27 May 2012.
  5. ^ a b Illingworth DV, Elsner C, De Groot K, Flickinger GL, Mikhail G (February 1977). "A specific progesterone receptor of myometrial cytosol from the rhesus monkey". Journal of Steroid Biochemistry. 8 (2): 157–160. doi:10.1016/0022-4731(77)90040-1. PMID 405534.
  6. ^ "Recent Animal Drug Approvals". U.S. Food and Drug Administration (FDA). 2 December 2024. Retrieved 21 December 2024. Public Domain This article incorporates text from this source, which is in the public domain.
  7. ^ https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/16365