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Pregnenolone
Systematic (IUPAC) name
3β-hydroxypregn-5-en-20-one
Identifiers
CAS number 145-13-1
ATC code none
PubChem 8955
DrugBank EXPT02608
Chemical data
Formula C 21H32O2  
Mol. mass 316.483 g/mol
Pharmacokinetic data
Bioavailability  ?
Metabolism  ?
Half life  ?
Excretion  ?
Therapeutic considerations
Pregnancy cat.  ?
Legal status
Routes  ?
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Pregnenolone is a steroid hormone involved in the steroidogenesis of progesterone, mineralocorticoids, glucocorticoids, androgens, and estrogens. As such it is a prohormone. Pregnenolone is a GABAA antagonist and increases neurogenesis in the hippocampus.[1]

Contents

Chemistry

Like other steroids, pregnenolone consists of four interconnected cyclic hydrocarbons. It contains ketone and hydroxyl functional groups, two methyl branches, and a double bond at C5, in the B cyclic hydrocarbon ring. Like all steroid hormones, it is hydrophobic. Its esterified version, pregnenolone sulfate, is water-soluble.

Synthesis

Production of Pregnenolone from Cholesteol and further metabolism
Reaction: Pregnenolone-Progesterone

Pregnenolone is synthesized from cholesterol. This conversion involves hydroxylation at the side-chain at C20 and C22 positions, with cleavage of the side-chain. The enzyme performing this task is cytochrome P450scc, located in the mitochondria, and controlled by pituitary tropic hormones, such as ACTH, FSH, LH.

Prohormone

Pregnenolone undergoes further steroid metabolism in one of three ways.

  • Pregnenolone can be converted to androsta-5,16-dien-3 beta-ol by 16-ene synthetase.

Neurosteroid

Pregnenolone and its sulfate, like dehydroepiandrosterone and its sulfate and progesterone, belong to the group of neurosteroids that are found in high concentrations in certain areas in the brain, and are synthesized there. Neurosteroids affect synaptic functioning, are neuroprotective, and enhance myelinization. Pregnenolone and its sulfate ester are under investigation for their potential to improve cognitive and memory functioning.[2]
Pregnenolone sulfate was shown to activate the Transient Receptor Potential M3 ion channel in hepatocytes and pancreatic islets causing calcium entry and subsequent insulin release.[3]

Additional images

Steroidogenesis, showing pregnenolone near top left.

References

  1. ^ Mayo, W; Lemaire, V; Malaterre, J; Rodriguez, Jj; Cayre, M; Stewart, Mg; Kharouby, M; Rougon, G; Le, Moal, M; Piazza, Pv; Abrous, Dn (January 2005). "Pregnenolone Sulfate Enhances Neurogenesis and Psa-Ncam in Young and Aged Hippocampus". Neurobiology of Aging 26 (1): 103–14. doi:10.1016/j.neurobiolaging.2004.03.013. PMID 15585350.  
  2. ^ Vallée M, Mayo W, Le Moal M (2001). "Role of pregnenolone, dehydroepiandrosterone and their sulfate esters on learning and memory in cognitive aging.". Brain Res Brain Res Rev 37 (1-3): 301–12. doi:10.1016/S0165-0173(01)00135-7. PMID 11744095.  
  3. ^ Wagner TF, Loch S, Lambert S, et al. (November 2008). "Transient receptor potential M3 channels are ionotropic steroid receptors in pancreatic beta cells". Nature cell biology 10: 1421. doi:10.1038/ncb1801. PMID 18978782.  
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