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| Names | |
|---|---|
| IUPAC name 16α-Hydroxypregn-4-ene-3,20-dione | |
| Systematic IUPAC name (1R,2R,3aS,3bS,9aR,9bS,11aS)-1-Acetyl-2-hydroxy-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 16α-OHP; 16α-OH-PROG | |
| Identifiers | |
3D model (JSmol) | |
| ChEBI | |
| ChEMBL | |
| ChemSpider | |
| UNII | |
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| Properties | |
| C21H30O3 | |
| Molar mass | 330.468 g·mol−1 |
Except where otherwise noted, data are given for materials in theirstandard state (at 25 °C [77 °F], 100 kPa). | |
16α-Hydroxyprogesterone (16α-OHP), also known as16α-hydroxypregn-4-ene-3,20-dione, is a minorendogenousprogestogensteroid hormone and ametabolite ofprogesterone that is formed in lower amounts than17α-hydroxyprogesterone (17α-OHP).[1] It occurs inmicromolar concentrations and itsphysiological relevance hence is questionable.[1] However, it may accumulate in targettissues and could have a physiological role in thereproductive system andmammary gland development as well as thecardiovascular andcentral nervous systems.[1]
16α-OHP is formed from progesterone via 16α-hydroxylation primarily byCYP17A1 and primarily insteroidogenic tissues including theadrenal glands,testes, andovaries.[1] It is alsosynthesized from progesterone duringpregnancy byhepaticcytochrome P450enzymes likeCYP3A4 andCYP1A1 in thefetalliver as well asplacenta.[1] It appears to be an end metabolite of progesterone and does not seem to be furthermetabolized.[1]
16α-OHP has approximately 67% and 43% of theaffinity of progesterone for thePR-A andPR-B, respectively, and acts as anagonist of these receptors similarly to progesterone.[1] It was found to producenatriuresis similar to that produced byspironolactone when administered to humans, suggesting that it also hasantimineralocorticoid activity similarly to progesterone.[1] However, surprisingly, 16α-OHP showed low affinity for themineralocorticoid receptor (MR) of greater than 1 μM (compared to 1 nM for progesterone) and showed noantagonism of the MR at up to a concentration of 1 μM (whereas progesterone shows potent such activity).[1] However, the findings of another study suggested that 16α-OHP antagonizes the effects ofaldosterone via the MR, and it may still be possible that 16α-OHP has significant antimineralocorticoid activity in some cells in spite of its weak MR affinity.[1]
