17α-Hydroxypregnenolone

17α-Hydroxypregnenolone is a pregnane (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.[1] High levels are also achieved during pregnancy. It is also a known neuromodulator.

17α-Hydroxypregnenolone

Pharmacokinetic data
Metabolism	Adrenal, Gonads
Identifiers
IUPAC name 3β,17α-dihydroxypregn-5-en-20-one
CAS Number	387-79-1^Y
PubChem CID	3032570
ChemSpider	17215939^Y
UNII	77ME40334S
ChEBI	CHEBI:28750^N
CompTox Dashboard (EPA)	DTXSID20894988
ECHA InfoCard	100.006.239
Chemical and physical data
Formula	C21H32O3
Molar mass	332.484 g·mol^−1
3D model (JSmol)	Interactive image
Melting point	268 °C (514 °F)
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
^NY (what is this?)  (verify)

Prohormone

17α-Hydroxypregnenolone 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 17α-hydroxypregenolone represents an intermediary in the Δ⁵ pathway that leads from pregnenolone to DHEA. 17α-Hydroxypregneolone is also converted to 17α-hydroxyprogesterone, a prohormone for glucocorticosteroids and androstenedione through the activity of 3α-hydroxysteroid dehydrogenase.

Clinical use

Measurements of 17α-hydroxypregnenolone are useful in the diagnosis of certain forms of congenital adrenal hyperplasia.[2] In patients with congenital adrenal hyperplasia due to 3β-hydroxysteroid dehydrogenase deficiency 17α-hydroxypregnenolone is increased, while in patients with congenital adrenal hyperplasia due to 17α-hydroxylase deficiency levels are low to absent.

Neurosteroid

17α-hydroxypregnenolone is a known neuromodulator as its acts in the central nervous system. Specifically, it is known to modulate locomotion.[3]

See also

• Congenital adrenal hyperplasia

Additional images

• 
  Steroidogenesis

References

1. Hill M, Lukác D, Lapcík O, Sulcová J, Hampl R, Pouzar V, Stárka L (April 1999). "Age relationships and sex differences in serum levels of pregnenolone and 17-hydroxypregnenolone in healthy subjects". Clinical Chemistry and Laboratory Medicine. 37 (4): 439–47. doi:10.1515/CCLM.1999.072. PMID 10369116.
2. Riepe FG, Mahler P, Sippell WG, Partsch CJ (September 2002). "Longitudinal study of plasma pregnenolone and 17-hydroxypregnenolone in full-term and preterm neonates at birth and during the early neonatal period". The Journal of Clinical Endocrinology and Metabolism. 87 (9): 4301–6. doi:10.1210/jc.2002-020452. PMID 12213889.
3. Tsutsui K, Haraguchi S, Vaudry H (September 2018). "7α-Hydroxypregnenolone regulating locomotor behavior identified in the brain and pineal gland across vertebrates". General and Comparative Endocrinology. 265: 97–105. doi:10.1016/j.ygcen.2017.09.014. PMID 28919448.