Altrenogest (also known as Allyltrenbolone; A35957; RU2267; DRC6246; R-2267; A-35957; RU-2267; Allyl trenbolone; REGU-MATE; Regumate) is a progestogen structurally related to veterinary steroid trenbolone. It is a synthetic trienic C21 steroidal progestomimetic, belonging to the 19-nor-testosterone series. It is an orally active (pro)gestagen. Like all steroids, altrenogest acts by its liposolubility by penetrating the target cells where it binds to specific receptors. In veterinary medicine, altrenogest is used in gilts and mares for zootechnical purposes (oestrus synchronization).

Physicochemical Properties

Molecular Formula	C21H26O2
Molecular Weight	310.43
Exact Mass	310.193
CAS #	850-52-2
Related CAS #	Altrenogest-d5
PubChem CID	10041070
Appearance	Light yellow to yellow solid powder
Density	1.1±0.1 g/cm3
Boiling Point	495.6±45.0 °C at 760 mmHg
Melting Point	120ºC
Flash Point	210.1±21.3 °C
Vapour Pressure	0.0±2.9 mmHg at 25°C
Index of Refraction	1.594
LogP	3.49
Hydrogen Bond Donor Count	1
Hydrogen Bond Acceptor Count	2
Rotatable Bond Count	2
Heavy Atom Count	23
Complexity	665
Defined Atom Stereocenter Count	4
SMILES	C[C@]12C=CC3=C4CCC(=O)C=C4CC[C@H]3[C@@H]1CC[C@]2(CC=C)O
InChi Key	VWAUPFMBXBWEQY-ANULTFPQSA-N
InChi Code	InChI=1S/C21H26O2/c1-3-10-21(23)12-9-19-18-6-4-14-13-15(22)5-7-16(14)17(18)8-11-20(19,21)2/h3,8,11,13,18-19,23H,1,4-7,9-10,12H2,2H3/t18-,19+,20+,21+/m1/s1
Chemical Name	(8S,13S,14S,17R)-17-allyl-17-hydroxy-13-methyl-1,2,6,7,8,13,14,15,16,17-decahydro-3H-cyclopenta[a]phenanthren-3-one
Synonyms	Allyltrenbolone; A 35957; A-35957;DRC 6246; R 2267; A35957; RU2267; Altrenogest; Allyl trenbolone; REGU-MATE; Regumate; RU 2267; RU-2267.
HS Tariff Code	2934.99.9001
Storage	Powder-20°C 3 years 4°C 2 years In solvent -80°C 6 months -20°C 1 month
Shipping Condition	Room temperature (This product is stable at ambient temperature for a few days during ordinary shipping and time spent in Customs)

Biological Activity

ln Vitro	The progestogen altrenogest (Allyltrenbolone) shares structural similarities with the veterinary steroid trenbolone. The degree of donor-recipient synchronization needed for a successful embryo transfer appears to be extended when mares receiving embryos are treated with Altrenogest (Allyltrenbolone)[1]. When it comes to controlling estrous behavior and the duration between estrus and ovulation, the gel and oil forms of Altrenogest (Allyltrenbolone) work equally well. therapy with altrenogest (Allyltrenbolone) that is initiated later in the diestrus seems to increase the likelihood of ovulation during therapy. When ovulation and luteolysis occur during treatment, the luteal phase that follows is often prolonged because the CL does not regress[2].
ln Vivo
Animal Protocol
References	[1]. Parry-Weeks, L.C. and D.W. Holtan, Effect of altrenogest on pregnancy maintenance in unsynchronized equine embryo recipients. J Reprod Fertil Suppl, 1987. 35: p. 433-8. [2]. Persistence of the luteal phase following ovulation during altrenogest treatment in mares. Theriogenology, 1996. 46(5): p. 799-811.
Additional Infomation	Altrenogest is a 3-hydroxy steroid. Altrenogest, also known as allyltrenbolone, is a steroidal progestin that is widely used in veterinary medicine to suppress estrus in animals.

Solubility Data

Solubility (In Vitro)

DMSO:62 mg/mL (199.7 mM) Water:<1 mg/mL Ethanol:2 mg/mL (6.4 mM)

Solubility (In Vivo)

Solubility in Formulation 1: ≥ 3 mg/mL (9.66 mM) (saturation unknown) in 10% DMSO + 40% PEG300 + 5% Tween80 + 45% Saline (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 30.0 mg/mL clear DMSO stock solution to 400 μL PEG300 and mix evenly; then add 50 μL Tween-80 to the above solution and mix evenly; then add 450 μL normal saline to adjust the volume to 1 mL. Preparation of saline: Dissolve 0.9 g of sodium chloride in 100 mL ddH₂ O to obtain a clear solution. Solubility in Formulation 2: ≥ 3 mg/mL (9.66 mM) (saturation unknown) in 10% DMSO + 90% (20% SBE-β-CD in Saline) (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 30.0 mg/mL clear DMSO stock solution to 900 μL of 20% SBE-β-CD physiological saline solution and mix evenly. Preparation of 20% SBE-β-CD in Saline (4°C，1 week): Dissolve 2 g SBE-β-CD in 10 mL saline to obtain a clear solution. Solubility in Formulation 3: ≥ 3 mg/mL (9.66 mM) (saturation unknown) in 10% DMSO + 90% Corn Oil (add these co-solvents sequentially from left to right, and one by one), clear solution. For example, if 1 mL of working solution is to be prepared, you can add 100 μL of 30.0 mg/mL clear DMSO stock solution to 900 μL of corn oil and mix evenly.  (Please use freshly prepared in vivo formulations for optimal results.)

Preparing Stock Solutions		1 mg	5 mg	10 mg
	1 mM	3.2213 mL	16.1067 mL	32.2134 mL
	5 mM	0.6443 mL	3.2213 mL	6.4427 mL
	10 mM	0.3221 mL	1.6107 mL	3.2213 mL

*Note: Please select an appropriate solvent for the preparation of stock solution based on your experiment needs. For most products, DMSO can be used for preparing stock solutions (e.g. 5 mM, 10 mM, or 20 mM concentration); some products with high aqueous solubility may be dissolved in water directly. Solubility information is available at the above Solubility Data section. Once the stock solution is prepared, aliquot it to routine usage volumes and store at -20°C or -80°C. Avoid repeated freeze and thaw cycles.