||Pregnenolone is an endogenous steroid hormone for inhibition of M1 receptor and M3 receptor-mediated currents with IC50 of 11.4 μM and 6.0 μM, respectively. Pregnenolone has memory-enhancing effects, used in the treatment of fatigue, Alzheimer’s disease, trauma and injuries.
||cAMP | Calcium Channel | M1 receptor | M3 receptor|
|J Steroid Biochem Mol Biol. 2000 Dec 1;75(1):1-10. |
|Pregnenolone stimulates LNCaP prostate cancer cell growth via the mutated androgen receptor.[Pubmed: 11179903]|
|Pregnenolone (P(5)), a common precursor of many steroids, is present in the blood of normal adult men at concentrations of 1-3 nM. In vitro, P(5) was found to stimulate LNCaP-cell proliferation 7-8-fold at a physiological concentration (2 nM), and 3-4-fold at a subphysiological concentration (0.2 nM). Growth stimulation at the 2-nM concentration was comparable with that of the androgen, dihydrotestosterone at its physiological concentration (0.5 nM; 9-10-fold increase in cell number).
METHODS AND RESULTS:
To determine whether P(5) or its metabolites were mediating this growth response, LNCaP cells were incubated with [3H]P(5) and high-performance liquid chromatography (HPLC) was performed.
After a 48-h exposure, two unidentified metabolites were detected. Although, the P(5) metabolites slightly increased LNCaP-cell growth in vitro, their effect was significantly less than P(5) alone, suggesting that the growth stimulation was mediated by P(5) itself. We further showed that P(5) sustained its proliferative activity in vivo and stimulated the growth of LNCaP-tumor xenografts in intact male SCID mice as well as in castrated animals. In order to determine whether P(5) was binding to a specific site in LNCaP cells, receptor binding studies were performed. Scatchard analysis predicted for a single class of binding sites with K(d)=1.4 nM. Studies were performed to determine the effects of P(5) on transcription mediated by wild-type and LNCaP androgen receptors. P(5) was shown to activate transcription through the LNCaP androgen receptor (AR), but not the wild-type AR. This implies that P(5) most likely stimulates LNCaP-cell proliferation through binding to the cellular mutated AR present in LNCaP cells. We have also demonstrated that drugs designed to be antagonists of the androgen, progesterone and estrogen receptors, and one of our novel compounds designed to be an inhibitor of androgen synthesis, were potent inhibitors of the AR-mediated transcriptional activity induced by P(5), and were able to inhibit LNCaP-cell proliferation.
These findings suggest that some prostate cancer patients who appear to become hormone-independent may have tumors which are stimulated by P(5) via a mutated AR and that these patients could benefit from treatment with antiestrogens, antiprogestins, or with some of our novel androgen synthesis inhibitors.
|J Steroid Biochem Mol Biol. 1994 Jul;50(1-2):91-100. |
|Pregnenolone and dehydroepiandrosterone as precursors of native 7-hydroxylated metabolites which increase the immune response in mice.[Pubmed: 8049138]|
|Dehydroepiandrosterone (DHEA) and Pregnenolone (PREG) were both metabolized by homogenates of brain, spleen, thymus, perianal skin, ventral skin, intestine, colon, coecum and muscle tissues from mice.
METHODS AND RESULTS:
The use of 2H-labeled substrates and of the twin ion technique of gas chromatography-mass spectrometry permitted identification of 7 alpha-hydroxy-DHEA and of 5-androstene-3 beta, 17 beta-diol as DHEA metabolites in digests of all tissues.
The extent of PREG metabolism was much lower than for DHEA with all tissues but amounts of the main transformation product were sufficient in brain, spleen and ventral skin digests for identification with 7 alpha-hydroxy-PREG. Dimethylsulfoxide (DMSO) solutions of DHEA, PREG and of their 7-hydroxylated metabolites were injected at different doses and time intervals prior to proximal subcutaneous administration of a lysozyme antigen. Quantities of anti-lysozyme IgG were measured in the serum of treated mice and compared with that from sham-treated animals. Increase of anti-lysozyme IgG was obtained with DHEA and PREG (1 g/kg) when injected 2 h prior to lysozyme. Much lower doses (160 times less) of 7 alpha-hydroxy-DHEA and -PREG were also found to be significantly active when administered at the moment of lysozyme injection. A larger dose of 7 beta-hydroxy-DHEA (50 mg/kg) was necessary for a similar effect.
These results suggest that in tissues where immune response takes place, the locally-produced 7-hydroxy metabolites of PREG and DHEA are involved in a process which may participate in the physiological regulation of the body's immune response.
|Psychiatry Clin Neurosci. 2014 Jun;68(6):432-40. |
|Pregnenolone treatment reduces severity of negative symptoms in recent-onset schizophrenia: an 8-week, double-blind, randomized add-on two-center trial.[Pubmed: 24548129]|
|Management of recent-onset schizophrenia (SZ) and schizoaffective disorder (SA) is challenging owing to frequent insufficient response to antipsychotic agents. This study aimed to test the efficacy and safety of the neurosteroid Pregnenolone in patients with recent-onset SZ/SA.
METHODS AND RESULTS:
Sixty out- and inpatients who met DSM-IV criteria for SZ/SA, with suboptimal response to antipsychotics were recruited for an 8-week, double-blind, randomized, placebo-controlled, two-center add-on trial, that was conducted between 2008 and 2011. Participants were randomized to receive either Pregnenolone (50 mg/day) or placebo added on to antipsychotic medications. The primary outcome measures were the Positive and Negative Symptoms Scale and the Assessment of Negative Symptoms scores. Secondary outcomes included assessments of functioning, and side-effects.
Analysis was by linear mixed model. Fifty-two participants (86.7%) completed the trial. Compared to placebo, adjunctive Pregnenolone significantly reduced Positive and Negative Symptoms Scale negative symptom scores with moderate effect sizes (d = 0.79). Significant improvement was observed in weeks 6 and 8 of Pregnenolone therapy among patients who were not treated with concomitant mood stabilizers (arms × visit × mood stabilizers; P = 0.010). Likewise, Pregnenolone significantly reduced Assessment of Negative Symptoms scores compared to placebo (d = 0.57), especially on blunted affect, avolition and anhedonia domain scores. Other symptoms, functioning, and side-effects were not significantly affected by adjunctive Pregnenolone. Antipsychotic agents, benzodiazepines and sex did not associate with Pregnenolone augmentation. Pregnenolone was well tolerated.
Thus, add-on Pregnenolone reduces the severity of negative symptoms in recent-onset schizophrenia and schizoaffective disorder, especially among patients who are not treated with concomitant mood stabilizers. Further studies are warranted.