17α-hydroxyprogesterone 17α-hydroxyprogesterone 17α-hydroxyprogesterone (17α-ohp), also known as 17-oh progesterone (17-ohp), or hydroxyprogesterone (ohp), is an endogenous progestogen steroid hormone related to progesterone. it is also a chemical intermediate in the biosynthesis of many other endogenous steroids, including androgens, estrogens, glucocorticoids, and mineralocorticoids, as well as neurosteroids. not to be confused with hydroxyprogesterone caproate or hydroxyprogesterone acetate. 17α-hydroxyprogesterone names iupac name 17α-hydroxypregn-4-ene-3,20-dione systematic iupac name (1r,3as,3br,9ar,9bs,11as)-1-acetyl-1-hydroxy-9a,11a-dimethyl-1,2,3,3a,3b,4,5,8,9,9a,9b,10,11,11a-tetradecahydro-7h-cyclopentaphenanthren-7-one other names hydroxyprogesterone (inn) identifiers cas number 68-96-2 3d model (jsmol) interactive image chebi chebi:17252 chembl chembl1062 chemspider 6002 echa infocard 100.000.636 iuphar/bps 5104 pubchem cid 6238 unii 21807m87j2 comptox dashboard (epa) dtxsid6040747 inchi inchi=1s/c21h30o3/c1-13(22)21(24)11-8-18-16-5-4-14-12-15(23)6-9-19(14,2)17(16)7-10-20(18,21)3/h12,16-18,24h,4-11h2,1-3h3/t16-,17+,18+,19+,20+,21+/m1/s1key: dbpwssgdrrhunt-cegnmafcsa-n smiles cc(=o)c1(ccc2c1(ccc3c2ccc4=cc(=o)ccc34c)c)o properties chemical formula c21h30o3 molar mass 330.46 g/mol melting point 219.5 except where otherwise noted, data are given for materials in their standard state (at 25 °c , 100 kpa). infobox references biological activity 17α-ohp is an agonist of the progesterone receptor (pr) similarly to progesterone, albeit weakly in comparison. in addition, it is an antagonist of the mineralocorticoid receptor (mr) as well as a partial agonist of the glucocorticoid receptor (gr), albeit with very low potency (ec50 >100-fold less relative to cortisol) at the latter site, also similarly to progesterone. relative affinities (%) of hydroxyprogesterone and related steroids compoundhpr-ahpr-brbprrbgrrber progesterone100100100<1<1 17α-hydroxyprogesterone1131<1 hydroxyprogesterone caproate2630284<1 hydroxyprogesterone acetate38461153 ? notes: values are percentages (%). reference ligands (100%) were progesterone for the pr, dexamethasone for the gr, and estradiol for the er. sources: see template. biochemistry steroidogenesis, showing 17α-ohp around the left-middle among the pregnenes. biosynthesis 17α-ohp is derived from progesterone via 17α-hydroxylase (encoded by cyp17a1) 17α-ohp increases in the third trimester of pregnancy primarily due to fetal adrenal production. this steroid is primarily produced in the adrenal glands and to some degree in the gonads, specifically the corpus luteum of the ovary. normal levels are 3-90 ng/dl in children, and in women, 20-100 ng/dl prior to ovulation, and 100-500 ng/dl during the luteal phase. measurement measurements of levels of 17α-ohp are useful in the evaluation of patients with suspected congenital adrenal hyperplasia as the typical enzymes that are defective, namely 21-hydroxylase and 11β-hydroxylase, lead to a build-up of 17α-ohp. in contrast, the rare patient with 17α-hydroxylase deficiency will have very low or undetectable levels of 17α-ohp. 17α-ohp levels can also be used to measure contribution of progestational activity of the corpus luteum during pregnancy as progesterone but note, 17α-ohp is also contributed by the placenta. immunoassays like ria (radioimmunoassay) or irma (immunoradiometric assay) used to clinically determine 17α-ohp are prone to cross-reactivity with the 17α-ohp steroid precursors and their sulphated conjugates. gas or liquid chromatography and mass spectrometry (e.g. lc-ms/ms) achieves greater specificity than immunoassays. measurement of 17α-ohp by lc-ms/ms improves newborn screening for congenital adrenal hyperplasia due to 21-hydroxylase deficiency, because 17α-ohp steroid precursors and their sulphated conjugates which are present in the first two days after birth and longer in pre-term neonates, cross-react in immunoassays with 17α-ohp, giving falsely high 17α-ohp levels. pharmacology pharmacokinetics although 17α-ohp has not been used as a medication, its pharmacokinetics have been studied and reviewed. medical uses