17-Hydroxypregnenolone

17-Hydroxypregnenolone

Systematic (IUPAC) name
3β,17-dihydroxypregn-5-en-20-one
Pharmacokinetic data
Metabolism	Adrenal, Gonads
Identifiers
CAS Number	387-79-1 Y
PubChem	CID: 3032570
ChemSpider	17215939 Y
ChEBI	CHEBI:28750 N
Chemical data
Formula	C21H32O3
Molecular mass	332.48 g/mol
SMILES CC[C@@]2(O)CC[C@H]1[C@@H]3CCC4CC(O)C(=O)C[C@]4(C)[C@H]3CC[C@@]12C
InChI InChI=1S/C21H34O3/c1-4-21(24)10-8-16-14-6-5-13-11-17(22)18(23)12-19(13,2)15(14)7-9-20(16,21)3/h13-17,22,24H,4-12H2,1-3H3/t13?,14-,15+,16+,17?,19+,20+,21-/m1/s1 Y Key:QPLFSAZMHUAMKE-FOCOMJRBSA-N Y
Physical data
Melting point	268 °C (514 °F)
NY (what is this?)  (verify)

17-Hydroxypregnenolone (also 17-OH-pregnenolone and 17α-hydroxypregnenolone), is a C21 steroid that is obtained by hydroxylation of pregnenolone at the C17α position. This step is performed by the mitochondrial cytochrome P450 enzyme 17α-hydroxylase (CYP17A1) that is present in the adrenal and gonads. Peak levels are reached in humans at the end of puberty and then decline. High levels are also achieved during pregnancy.

Prohormone

17 OH–pregnenolone is converted from pregnenolone and gives rise to DHEA (below) and to 17 OH-progesterone (to its right)

17-OH-pregnenolone is considered a prohormone in the formation of dehydroepiandrosterone (DHEA), itself a prohormone of the sex steroids.

This conversion is mediated by the enzyme 17,20 lyase. As such 17-OH-pregenolone represents an intermediary in the delta-5-pathway that leads from pregnenolone to DHEA. 17-hydroxypregneolone is also converted to 17-hydroxyprogesterone, a prohormone for glucocorticosteroids and androstenedione through the activity of 3-hydroxysteroid dehydrogenase.

Neurohormone

There is some evidence that 17-OH-pregnenolone may have activity as a neurosteroid.

Clinical use

Measurements of 17-OH-pregnenolone are useful in the diagnosis of certain forms of congenital adrenal hyperplasia. In patients with congenital adrenal hyperplasia due to 3 beta-hydroxysteroid dehydrogenase deficiency 17-OH-pregnenolone is increased, while in patients with congenital adrenal hyperplasia due to 17 alpha-hydroxylase deficiency levels are low to absent.

See also

Congenital adrenal hyperplasia

Additional images

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  Steroidogenesis