MELENGESTROL

Details

Stereochemistry	ABSOLUTE
Molecular Formula	C23H30O3
Molecular Weight	354.4825
Optical Activity	UNSPECIFIED
Defined Stereocenters	6 / 6
E/Z Centers	0
Charge	0

SHOW SMILES / InChI

Structure Search

SMILES

CC(=O)[C@@]1(O)C(=C)C[C@H]2[C@@H]3C=C(C)C4=CC(=O)CC[C@]4(C)[C@H]3CC[C@]12C

InChI

InChIKey=OKHAOBQKCCIRLO-IBVJIVQJSA-N

InChI=1S/C23H30O3/c1-13-10-17-18(21(4)8-6-16(25)12-19(13)21)7-9-22(5)20(17)11-14(2)23(22,26)15(3)24/h10,12,17-18,20,26H,2,6-9,11H2,1,3-5H3/t17-,18+,20+,21-,22+,23+/m1/s1

HIDE SMILES / InChI

Molecular Formula	C23H30O3
Molecular Weight	354.4825
Charge	0
Count

Stereochemistry	ABSOLUTE
Additional Stereochemistry	No
Defined Stereocenters	6 / 6
E/Z Centers	0
Optical Activity	UNSPECIFIED

Description
Sources: http://vahs.net/wp-content/uploads/Stefanie-Anderson-Melengestrol-acetate-MGA.pdf
Curator's Comment: Description was created based on several sources, including https://www.ncbi.nlm.nih.gov/pubmed/2676933 and http://www.fda.gov/AnimalVeterinary/Products/ApprovedAnimalDrugProducts/FOIADrugSummaries/ucm064715.htm

Melengestrol is a steroidal progestin and antineoplastic agent which was never marketed. An acylated derivative, melengestrol acetate, is used as a growth promoter in animals. Melengestrol acetate (MGA) is one of six steroidal hormone growth promoters approved for use in Canada and USA. These products are used to improve growth rate and feed efficiency, as well as to suppress estrus in beef heifers (CFIA 2008). They are not approved for use in any species other than beef cattle meant for slaughter. MGA is the only drug of its kind that is administered in animal feed, and its labelled dose in Canada is 0.4mg per heifer per day (CFIA 2008). A mandatory withdrawal of 2 days before slaughter is applied to any animal that is administered MGA.

Approval Year

Targets

Primary Target	Pharmacology	Potency
C. albicans growth 3 Target ID: C. albicans growth Sources: https://www.ncbi.nlm.nih.gov/pubmed/24277040	Inhibitor 8504
Progesterone receptor 61 Target ID: CHEMBL208 Sources: https://www.ncbi.nlm.nih.gov/pubmed/15713363	Agonist 2752	0.418 nM [IC50]
Rat prostatic tumor growth 2 Target ID: Rat prostatic tumor growth Sources: http://www.ncbi.nlm.nih.gov/pubmed/2268413	Inhibitor 8504

Conditions

Condition	Modality	Targets	Highest Phase	Product
Suppression of estrus in Heifers 2 Sources: http://www.fda.gov/downloads/AnimalVeterinary/Products/ApprovedAnimalDrugProducts/FOIADrugSummaries/ucm061809.pdf	Preventing		Approved 8583	HEIFERMAX 500 Approved Use For increased rate of weight gain, improved feed efficiency, suppression of estrus in Heifers. Launch Date 2004
Prostate cancer 186 Sources: http://www.ncbi.nlm.nih.gov/pubmed/2268413	Primary		Basic research	Unknown Approved Use Unknown

Doses

Dose	Population	Adverse events
80 mg single, oral Highest studied dose Dose: 80 mg Route: oral Route: single Dose: 80 mg Sources: https://pubmed.ncbi.nlm.nih.gov/1100303/	healthy, ADULT Health Status: healthy Age Group: ADULT Sex: M+F Food Status: UNKNOWN Sources: https://pubmed.ncbi.nlm.nih.gov/1100303/	Sources: https://pubmed.ncbi.nlm.nih.gov/1100303/

PubMed

Title	Date	PubMed
Roles of hCG in Advancing Follicular Growth to Ovulation after Concurrent Injections of PGF(2α) and GnRH in Postpubertal Holstein Heifers Bearing a CL.	2010-12-01	21151654
The watershed as a conceptual framework for the study of environmental and human health.	2009-02-18	20508751

Patents

Sample Use Guides

In Vivo Use Guide

Melengestrol (HEIFERMAX® 500) should be thoroughly mixed in liquid Type C medicated feed which must be fed at 0.5 to 2.0 pounds per head daily to provide 0.25 to 0.5 mg of melengestrol acetate per head per day. Average daily intakes approximating the middle of this range provide the most optimal and economical improvements in rate of weight gain and feed utilization. Constant daily intakes of 0.35 to 0.50 mg per head per day give a high degree of estrus suppression. Levels of 0.25 to 0.35 mg provide a lower but still effective degree of estrus suppression.

Route of Administration: Oral

In Vitro Use Guide

Total body mass and snout-vent length of X. laevis larvae were significantly reduced by the 100 ng/L melengestrol

Substance Class	Chemical Created by `admin` on `Mon Mar 31 19:32:40 GMT 2025` Edited by `admin` on `Mon Mar 31 19:32:40 GMT 2025`
Record UNII	BX98J4T6JU
Record Status	`Validated (UNII)`
Record Version

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Name

Type

Language

BDH-1921

Preferred Name

English

MELENGESTROL

Official Name

English

PREGNA-4,6-DIENE-3,20-DIONE, 17-HYDROXY-6-METHYL-16-METHYLENE-

Systematic Name

English

melengestrol [INN]

Common Name

English

17-HYDROXY-6-METHYL-16-METHYLENEPREGNA-4,6-DIENE-3,20-DIONE

Systematic Name

English

MELENGESTREL

Common Name

English

MELENGESTEROL

Common Name

English

Classification Tree Code System Code

CFR

21 CFR 558.342