Pharmacokinetic data
Metabolism Adrenal, Gonads
CAS Number 387-79-1 YesY
PubChem (CID) 3032570
ChemSpider 17215939 YesY
Chemical and physical data
Formula C21H32O3
Molar mass 332.48 g/mol
3D model (Jmol) Interactive image
Melting point 268 °C (514 °F)
 NYesY (what is this?)  (verify)

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.


17α-Hydroxypregnenolone is converted from pregnenolone and gives rise to DHEA (below) and to 17α-hydroxyprogesterone (to its right)

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.


There is some evidence that 17α-hydroxypregnenolone may have activity as a neurosteroid.[2]

Clinical use

Measurements of 17α-hydroxypregnenolone are useful in the diagnosis of certain forms of congenital adrenal hyperplasia.[3] 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.

See also

Additional images


  1. Hill, M; Lukác, D; Lapcík, O; Sulcová, J; Hampl, R; Pouzar, V; Stárka, L (1999). "Age relationships and sex differences in serum levels of pregnenolone and 17-hydroxypregnenolone in healthy subjects". Clinical chemistry and laboratory medicine : CCLM / FESCC. 37 (4): 439–47. doi:10.1515/CCLM.1999.072. PMID 10369116.
  2. Matsunaga, M; Ukena, K; Baulieu, EE; Tsutsui, K (2004). "7α-Hydroxypregnenolone acts as a neuronal activator to stimulate locomotor activity of breeding newts by means of the dopaminergic system". Proceedings of the National Academy of Sciences of the United States of America. 101 (49): 17282–7. doi:10.1073/pnas.0407176101. PMC 535386Freely accessible. PMID 15569930.
  3. Riepe FG, Mahler P, Sippell, Partsch CJ. 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 & Metabolism (2002) 87: 4301-4306

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