20α-Dihydroprogesterone

20α-Dihydroprogesterone
Names
	IUPAC name 20α-Hydroxypregn-4-en-3-one
	Systematic IUPAC name (1S,3aS,3bS,9aR,9bS,11aS)-1-[(1S)-1-Hydroxyethyl]-9a,11a-dimethyl-1,2,3,3a,3b,4,5,8,9,9a,9b,10,11,11a-tetradecahydro-7H-cyclopenta[a]phenanthren-7-one
	Other names 20α-DHP; 20α-Hydroxyprogesterone; 20α-OHP; Pregn-4-en-20α-ol-3-one
Identifiers
CAS Number	145-14-2 [yes];
3D model (JSmol)	Interactive image;
ChemSpider	83725;
EC Number	205-649-5;
MeSH	20-alpha-Dihydroprogesterone
PubChem CID	8956;
UNII	45630A64AC ;
CompTox Dashboard (EPA)	DTXSID10904767 ;
	InChI InChI=1S/C21H32O2/c1-13(22)17-6-7-18-16-5-4-14-12-15(23)8-10-20(14,2)19(16)9-11-21(17,18)3/h12-13,16-19,22H,4-11H2,1-3H3/t13-,16-,17+,18-,19-,20-,21+/m0/s1 Key: RWBRUCCWZPSBFC-RXRZZTMXSA-N;
	SMILES C[C@@H]([C@H]1CC[C@@H]2[C@@]1(CC[C@H]3[C@H]2CCC4=CC(=O)CC[C@]34C)C)O;
Properties
Chemical formula	C21H32O2
Molar mass	316.478 g/mol
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

20α-Dihydroprogesterone (20α-DHP), also known as 20α-hydroxyprogesterone (20α-OHP), is a naturally occurring, endogenous progestogen. It is a metabolite of progesterone, formed by the 20α-hydroxysteroid dehydrogenases (20α-HSDs) AKR1C1, AKR1C2, and AKR1C3 and the 17β-hydroxysteroid dehydrogenase (17β-HSD) HSD17B1. 20α-DHP can be transformed back into progesterone by 20α-HSDs and by the 17β-HSD HSD17B2. HSD17B2 is expressed in the human endometrium and cervix among other tissues. In animal studies, 20α-DHP has been found to be selectively taken up into and retained in target tissues such as the uterus, brain, and skeletal muscle.

20α-DHP has very low affinity for the progesterone receptor and is much less potent as a progestogen in comparison to progesterone, with about one-fifth of the relative progestogenic activity. It has also been found to act as an aromatase inhibitor and to inhibit the production of estrogen in breast tissue in vitro.

A single 200-mg oral dose of micronized progesterone has been found to result in peak levels of 20α-DHP of around 1 ng/mL after 2 hours. In another study however, peak levels of 20α-DHP were around 10 ng/mL during therapy with 300 mg/day oral micronized progesterone. 20α-DHP is formed from progesterone in the liver and in target tissues such as the endometrium. It appears to be more slowly eliminated than progesterone.

Levels of 5α-DHP have been quantified.