Not to be confused with Megestrol acetate.

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

Animal reproduction

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

Pharmacology

Pharmacodynamics

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

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

Generic names

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

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

References

  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.