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Pregnenolone

About: Pregnenolone is a research topic. Over the lifetime, 3539 publications have been published within this topic receiving 126444 citations. The topic is also known as: (3b)-3-hydroxy-Pregn-5-en-20-one & 3-Hydroxypregn-5-en-20-one.


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Journal ArticleDOI
TL;DR: The results are consistent with previous work suggesting that, a modest increase in acetylcholine release facilitates memory processes, while elevation beyond an optimal level is ineffective, Nevertheless, neurosteroids may be of value for reinforcing depressed cholinergic transmission in certain age-related memory disorders.

76 citations

Journal ArticleDOI
TL;DR: The demonstration of de novo steroid biosynthesis and of the cholesterol side-chain cleavage cytochrome P-450 in normal rat glial cells brings additional support to the concept of "neurosteroids".

76 citations

Journal ArticleDOI
TL;DR: In addition to possessing CYP11A1 and CYP17, it is equally important that a steroidogenic cell not contain other enzymes that drain the flux of pregnenolone to DHEA.
Abstract: The biosynthesis of dehydroepiandrosterone (DHEA) from cholesterol involves only two enzymes, both cytochrome P450s. The conversion of cholesterol to pregnenolone is mediated by cholesterol side-chain cleavage enzyme (CYP11A1), which is found in the mitochondria. The cleavage of pregnenolone to DHEA requires both the 17alpha-hydroxylase and 17,20-lyase activities of CYP17, which is found in the endoplasmic reticulum. These conversions require pairs of electron transfer proteins or redox partners, which are adrenodoxin and adrenodoxin reductase for CYP11A1 and cytochrome P450-oxidoreductase and cytochrome b5 for CYP17. In addition, the steroidogenic acute regulatory (StAR) protein regulates the flux of cholesterol into the biosynthetic pathway and represents the mechanism of acute regulation. Finally, in addition to possessing CYP11A1 and CYP17, it is equally important that a steroidogenic cell not contain other enzymes that drain the flux of pregnenolone to DHEA. These characteristics are illustrated by the fetal adrenal cortex and the zona reticularis, which are dedicated to the synthesis of DHEA and DHEA-sulfate.

76 citations

Journal ArticleDOI
TL;DR: Findings from the laboratory suggest that polyphosphoinositides may function as a cycloheximide-sensitive mediator in the steroidogenic action of ACTH.
Abstract: ACTH treatment in vivo enhances the activity of adrenal cytosol for supporting pregnenolone synthesis in adrenal mitochondria. Upon fractionation of adrenal cytosol by gel filtration through Sephadex G200, pregnenolone synthesisstimulating activity is eluted just after 3H2O(Kd = 1.1–2.1). This late eluting steroidogenic activity is enhanced by ACTH treatment and diminished by cycloheximide treatment, which also inhibits adrenal protein synthesis and ACTH-induced steroidogenesis. Chromatography on Sephadex G-10 yields even further separation of steroidogenic factor(s) from inactive substances; it appears that the active factor(s) adsorbs to Sephadex and that such adsorption is enhanced by a greater degree of cross-linking in the gel. The phospholipids, cardiolipin, diphosphoinositide, and triphosphoinositide, are recovered partly in adrenal cytosol and, by virtue of their polyphosphorylated head group, specifically stimulate mitochondrial pregnenolone synthesis. It seems likely that the ACTH effect on cyto...

76 citations

Journal ArticleDOI
TL;DR: The results suggest that the nucleus basalis magnocellularis-cortical pathway could be in part responsible for the promnesic effect of pregnenolone sulfate, which acts as a negative modulator of the GABA(A) receptor complex and positively modulates the N-methyl-D-aspartate receptor, possibly resulting in a global stimulatory effect on central cholinergic neurotransmission.

76 citations


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Performance
Metrics
No. of papers in the topic in previous years
YearPapers
202344
202255
202124
202028
201950
201835