Melengestrol acetate

Uses

Animal reproduction

MLGA is used in animal reproduction.

Pharmacology

Pharmacodynamics

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

Chemistry

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. 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. 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. 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. The only structural difference between MLGA and megestrol acetate is the presence of the C16 methylene group in the former.

Society and culture

Legal status

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.

Generic names

Melengestrol acetate is the generic name of the drug and its and . Melengestrol is the and of the unesterified free alcohol form.

Brand names

MLGA is marketed under the brand names Heifermax and MGA among others.

References

References

1. (14 November 2014). "The Dictionary of Drugs: Chemical Data: Chemical Data, Structures and Bibliographies". Springer.
2. "Melengestrol". Drugs.com.
3. (2010). "Wild Mammals in Captivity: Principles and Techniques for Zoo Management". University of Chicago Press.
4. (26 November 2009). "Analyses for Hormonal Substances in Food-Producing Animals". Royal Society of Chemistry.
5. (February 1977). "A specific progesterone receptor of myometrial cytosol from the rhesus monkey". Journal of Steroid Biochemistry.
6. (2 December 2024). "Recent Animal Drug Approvals".
7. https://animaldrugsatfda.fda.gov/adafda/app/search/public/document/downloadFoi/16365