Gourt Home::Gourt :: 17-Hydroxypregnenolone
| pregn-5-en-20-one, 3,17-dihydroxy-, (3beta)- | |
| CAS number * | |
| Empirical formula | C21H32O3 |
| Molecular weight | 332.48 |
| Bioavailability | |
| Metabolism | AdrenalGonads |
| Elimination half life | |
| Excretion | |
| Pregnancy category | |
| Physical properties | |
| Melting point | 268°C |
17-Hydroxypregnenolone, also 17-OH-pregnenolone and more precisely 17α-hydroxypregnenolone, is a C21 steroid that is obtained by hydroxylation of pregnenolone at the C17 alpha position. This step is performed by the mitochondrial cytochrome P450 enzyme 17α-hydroxylase that is present in the adrenal and gonads. Peak levels are reached in humans at the end of puberty and then decline.Hill M, Lukac D, Lapcik O, Sulcova J, Hampl R, Pouzar V, Starka L. Age relationships and sex differences in serum levels of pregnenolone and 17-hydroxypregnenolone in healthy subjects. Clin Chem Lab Med. 1999 Apr;37(4):439-47. PMID 10369116 High levels are also achieved during pregnancy.
Prohormone
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 prohomone 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 neurohormone.Matsunaga M, Ukena K, Baulieu EE, Tsutsui K 7alpha-Hydroxypregnenolone acts as a neuronal activator to stimulate locomotor activity of breeding newts by means of the dopaminergic system. Proc Natl Acad Sci USA 2004 Dec 7;101(49):17282-7. PMID 15569930
Clinical use
Measurements of 17-OH-pregnenolone are useful in the diagnosis of certain forms of congenital adrenal hyperplasia.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 * 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
References
External links
"17-Hydroxypregnenolone"