EnzymeimmunoassayforthedirectquantitativedeterminationofPregnenoloneinhumanserum.

Pregnenolone(3ß-hydroxypregn-5-en-20-one)isthefirststeroidtobederivedfromcholesterolinthepathwayofsteroidogenesis,anditisthecommonprecursorforalloftheadrenalandgonadalsteroids.ItsproductionoccursinthemitochondrionbycleavageoftheC-20sidechainofcholesterolbytheP-450SCCenzyme.Onceproduced,pregnenolonemaybeutilizedbytwopathwaysofsteroidogenesis.Pregnenolonemayeitherbeconvertedto17-OHpregnenoloneviatheenzymaticactionof17a-hydroxylaseortoprogesteroneviatheenzymaticactionof3ß-hydroxysteroiddehydrogenase.
Elevatedpregnenolonelevelsoccurinformsofcongenitaladrenalhyperplasia(CAH),dueto3ß-hydroxysteroiddehydrogenasedeficiencyor17a-hydroxylasedeficiencies.Higherlevelshavealsobeenreportedinwomenwithidiopathichirsutism.Studiesonpregnenolonelevelsinregardtosexandagedifferencesindicatethatmaximumlevelsoccuratapproximately17and16yearsofageforwomenandmen,whileminimumlevelsoccuratapproximately37and38yearsofageforwomenandmen,respectively.Ingeneral,womenwerefoundtohaveslightlyhighervalueswhencomparedtomen.
Manyareasofpregnenolonephysiologyremaintobeinvestigated.Currentresearchindicatesthatthedeterminationofpregnenoloneinserummaybeusefulforstudyingitsmetabolite,pregnenolonesulfate,whichhasbeenreportedtohavevariouseffectsinthemammalianbrainandcentralnervoussystem.