Simultaneous quantification of GABAergic 3α,5α/3α,5β neuroactive steroids in human and rat serum

The 3α,5α- and 3α,5β-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone enhance GABAergic neurotransmission and produce inhibitory neurobehavioral and anti-inflammatory effects. Despite substantial information on the progesterone derivative (3α,5α)-3-hydroxypregnan-20-one (3α,5α-THP, allopregnanolone), the physiological significance of the other endogenous GABAergic neuroactive steroids has remained elusive. Here, we describe the validation of a method using gas chromatography–mass spectrometry to simultaneously identify serum levels of the eight 3α,5α- and 3α,5β-reduced derivatives of progesterone, deoxycorticosterone, dehydroepiandrosterone and testosterone. The method shows specificity, sensitivity and enhanced throughput compared to other methods already available for neuroactive steroid quantification. Administration of pregnenolone to rats and progesterone to women produced selective effects on the 3α,5α- and 3α,5β-reduced neuroactive steroids, indicating differential regulation of their biosynthetic pathways. Pregnenolone administration increased serum levels of 3α,5α-THP (+1488%, p < 0.001), (3α,5α)-3,21-dihydroxypregnan-20-one (3α,5α-THDOC, +205%, p < 0.01), (3α,5α)-3-hydroxyandrostan-17-one (3α,5α-A, +216%, p < 0.001), (3α,5α,17β)-androstane-3,17-diol (3α,5α-A-diol, +190%, p < 0.01). (3α,5β)-3-hydroxypregnan-20-one (3α,5β-THP) and (3α,5β)-3-hydroxyandrostan-17-one (3α,5β-A) were not altered, while (3α,5β)-3,21-dihydroxypregnan-20-one (3α,5β-THDOC) and (3α,5β,17β)-androstane-3,17-diol (3α,5β-A-diol) were increased from undetectable levels to 271 ± 100 and 2.4 ± 0.9 pg ± SEM, respectively (5/8 rats). Progesterone administration increased serum levels of 3α,5α-THP (+1806%, p < 0.0001), 3α,5β-THP (+575%, p < 0.001), 3α,5α-THDOC (+309%, p < 0.001). 3α,5β-THDOC levels were increased by 307%, although this increase was not significant because this steroid was detected only in 3/16 control subjects. Levels of 3α,5α-A, 3α,5β-A and pregnenolone were not altered. This method can be used to investigate the physiological and pathological role of neuroactive steroids and to develop biomarkers and new therapeutics for neurological and psychiatric disorders.     

The involvement of cytochrome b5 in 5β-cholestane-3α,7α,12α-triol 25-hydroxylation and taurodeoxycholate 7α-hydroxylation of rat liver

Role of cytochrome b₅ in NADPH-supported 5β-cholestane-3α,7α,12α-triol 25-hydroxylation and taurodeoxycholate 7α-hydroxylation of rat liver microsomes was investigated using highly purified antibodies against cytochrome b₅. Anti-b₅ antibody strongly inhibited both hydroxylation reactions indicating that cytochrome b₅ is a functional component in these steroid hydroxylation systems. It was shown that the involvement of cytochrome b₅ in these systems could be altered by the conditions of the reaction systems.     

The identification and characterization of the c19o3 steroid metabolites of 5α-androstane-3β, 17β-diol produced by the canine prostate: 5α-androstane-3β, 6α, 17β-triol and 5α-androstane-3β, 7α, 17β-triol

This study has identified the polar metabolites of 5α-androstane-3β, 17β-diol(3β-diol) produced by the canine prostate. The major metabolite is 5α-androstane-3β, 7α, 17β-triol (7α-triol) accounting for approximately 80% of the total polar metabolites of 3β-diol. The remaining 20% is accounted for exclusively by another triol, 5α-androstane-3β, 6α, 17β-triol(6α-triol). This study has also characterized two enzymatic hydroxylases responsible for respective triol formation: 5α-androstane-3β, 17β-diol 6α-hydroxylase (6α-hydroxylase) and 5α-androstane-3β, 17β-diol 7α-hydroxylase (7α-hydroxylase). Both of these irreversible hydroxylases are located in the particulate fraction of the prostate and can utilize either NADH or NADPH as cofactor. Several $\text{in vitro}$ steroid inhibitors of these hydroxylases were identified including cholesterol, estradiol and diethylstilbestrol. Neither of the hydroxylases were found to be decreased by castration (3 months) when expressed as activity/DNA. Using a variety of C₁₉ androstane substrates, 6α- and 7α-triol were found to be major components of the total 3β-hydroxy-5α-androstane metabolites produced by the canine prostate.     

Synthesis of 5α-Androstane-3α,16α,17β-triol from 3β-hydroxy-5-androsten-17-one

5α-Androstane-3α, 16α 17β-triol was synthesized from 3β-hy-droxy-5-androsten-17-one. The procedure Involved catalytic hydrogenation of 3β-hydroxy-5-androsten-17-one to 3β-hydroxy-5α-androstan-17-one. This was followed by conversion of the 3β-hydroxy group to 3α-benzoyloxy group by the Mitsunobu reaction. Further treatment with isopropenyl acetate yielded 5α-androsten-16-ene-3α, 17-diol 3-benzoate 17-acetate. This was then converted to 3α, 17-dihydroxy-5α-androstan-16-one 3-benzoate 17-acetate via the unstable epoxide intermediate after treatment with $\text{m}$-cloroperoxybenzoic acid. LiAlH₄ reduction of this compound formed 5α-androstane-3α, 16α, 17β-trlol. ¹H and ¹³C NMR of various steroids are presented to confirm the structure of this compound.     

5α,6α- AND 5β,6β-dichloromethylene adducts of 3β-acetoxy-5-androsten-17-one

Both the 5α, 6α- and 5β, 6β-dichloromethylene adducts ($\text{2a}$ and $\text{2b}$) of 3β-acetoxy-5-androsten-17-one ($\text{1}$) are produced when the latter is exposed to dichlorocarbene generated from chloroform and base by Phase Transfer Catalysis using ultrasound as a means of agitation. The ¹H NMR substituent effects of 5α, 6α- and 5β, 6β-dichloromethylene on the angular methyl groups (Zürcher values) are given. The ¹³C NMR spectra for both compounds are presented and discussed.     

Bile acids. LXIV. Synthesis of 5α-cholestane-3α,7α,25-triol and esters of new 5α-bile acids

Interest in the structural requirements of a sterol or bile acid for maximal activity by an hepatic microsomal steroid 12α-hydroxylase prompted the preparation of 5α-cholestane-3α, 7α, 25-triol and 5α-analogs of 3α, 7α-dihydroxy-5β-cholane-24-carboxylic acid. Methyl 3α, 7α-dihydroxy-5β-cholane-24-carboxylate derived from methyl chenodeoxycholate via the Arndt-Eistert reaction was allomerized with Raney nickel in boiling p-cymene to provide a number of products of which methyl 3,7-dioxo-5β- and 5α-cholane-24-carboxylates, methyl 3-oxo-7α-hydroxy-5β-and 5α-cholane-24-carboxylates, were identified. Reduction with K-Selectride of methyl 3-oxo-7α-hydroxy-5β-cholane-24-carboxylate, provided a high yield of methyl 3α, 7α-dihydroxy-5α-cholane-24-carboxylate. Treatment of this ester with an excess of methyl magnesium iodide afforded 5α-cholestane-3α, 7α, 25-triol. The products were characterized by thin-layer and gas liquid chromatography, proton resonance, infrared and mass spectrometry.     

工程菌DH5α/pCW-PL-XE-TNFαm2的遗传稳定性

目的本基因工程大肠杆菌DH5α/pCW-PL-XE-TNFαm2所表达的靶向融合蛋白XE-TNFαm2已被初步证明具有用于清除艾滋病患者体内HIV病毒的前景。其目的蛋白表达水平为32%～36%细胞总蛋白。本研究旨在验证其遗传稳定性。方法工程菌株DH5α/pCW-PL-XE-TNFαm分别在LBAmp＋与LBAmp-二种固体培养基上逐日单菌落划线传代,32℃培养过夜。每间隔十代运用一般温控表达技术,确定其XE-TNFαm2的蛋白含量,最后比较分析各代之间目的蛋白（20.3 kDa）表达水平的差异情况。结果该重组基因工程菌连续传100代后XE-TNFαm2的蛋白表达水平没有明显差异（P〉0.05）;只是在上述两种情况下传至100代后将其置于4℃保藏4、5、6个月,其目的蛋白表达水平有8%的下降。本载体质粒含有的CIts857序列、PL启动子与T1T2末端终止序列,是确保目的基因稳定高表达的3个关键元件。结论本研究结果证明该工程菌DH5α/pCW-PL-XE-TNFαm2具有良好的遗传稳定性。     

Improved synthesis of 3α,7α,12α,24ξ -tetrahydroxy-5 β -cholestan-26-oic acid

This paper describes three simple and short methods for the conversion of cholic acid into cholylaldehyde with protected hydroxyl groups. The first method involves lithium aluminum hydride reduction of the tetrahydropyranyl ether of methyl cholate and oxidation of the resulting primary alcohol with pyridinium chlorochromate. The second method employs diborane for the reduction of the -COOH group to the -CH₂OH group, while the third method involves the reduction of 3α, 7α, 12α -triformyloxy-5β -cholan-24-oic acid (as the acid chloride) directly into 3α, 7α, 12α -triformyloxy-5β -cholan-24-al with TMA-ferride (tetramethylammonium hydridoirontetracarbonyl). The aldehyde obtained by any of the above methods underwent smooth Reformatsky reaction with ethyl α -bromopropionate to yield 3α, 7α, 12α, 24ξ -tetrahydroxy-5β -cholestan-26-oic acid.     

Biosynthesis of 1α,2α,3β-trihydroxy-p-menthane by Fusicoccum amygdali

Measurement of isotope ratios in 1α,2α,3β-trihydroxy-p-menthane, which has been biosynthesized in Fusicoccum amygdali from ³H- and ¹⁴C-labelled mevalonate and in its degradation product diosphenol indicates that: (a) four tritium atoms arising from [5-³H₂, 2-¹⁴C]MVA are retained, one more than suggested from the hydroxylation pattern, (b) menth-2-ene-1-ol is generated from an α-terpinyl cation through a 1,3-hydride shift and (c) trans-cleavage of an α-epoxide by hydrolysis gives 1α,2α,3β-trihydroxy-p-menthane.     

Synthesis of 3α,7α-dihydroxy-5β-androstan-17-one

A short and efficient method for the stereospecific synthesis of 3α,7α-dihydroxy-5β-androstan-17-one was accomplished from the readily available 4-androstene-3,17-dione. Key steps are the stereospecific and selective epoxidation of 4,6-androstadiene-3,17-dione, followed by hydrogenations with carefully selected reagents, solvents and reaction conditions.     

Studies on the effect of 5α-androstane-3α, 17α-diol in the canine prostate in vivo

Adult beagle dogs, castrated one month previously, were treated with 5α-androstane-3α, 17α-diol (total dose 300 mg) over a period of one month. Examination of the prostate after treatment showed no significant change in size, weight or histological appearance from the castrate dog prostate. Subsequent administration of 5α-androstane-3α, 17β-diol (300 mg) over the same period of time resulted in restoration of the prostate size, weight and histological appearance to that of the normal intact dog prostate. It is concluded that exogenously administered 5α-androstane-3α, 17α-diol does not promote prostatic growth in the castrate beagle dog.     

Simultaneous radioimmunoassay of testosterone,dihydrotestosterone, 5α-androstane-3α, 17β-diol and 5α-androstane-3β, 17β-diol in the plasma of adult male rats

A single thin layer chromatography and three antibodies were used for the specific radioimmunoassay of four androgens in pooled rat plasma (Sprague-Dawley adult males). The following values were found (pg/ml ± SD). Testosterone : 3, 138 ± 173; dihydrotestosterone : 374 ± 20; 5α-androstane-3α 17β-diol : 284 ± 24; 5α-androstane-3β, 17β-diol : 223 ± 11.     

Photochemical action spectrum of the co-inhibited 5β-cholestane-3α, 7α, 12α-triol 26-hydroxylase system

The inhibition of the mitochondrial hydroxylation of 5β-cholestane-3α, 7α, 12α-triol at the 26 position by a CO:O₂ gas mixture was maximally reversed by monochromatic light at the wavelength of 450 nm. This establishes the involvement of a cytochrome P450 dependent monooxygenase in the 26-hydroxylation of 5β-cholestane-3α, 7α, 12α-triol in rat liver mitochondria.     

Metabolism of 17β-hydroxy-2α,3α-cyclopropano-5α-androstane in the rabbit

The neutral urinary excretion products of 17β-hydroxy-2α,3α-cyclopropano-5α-androstane from the rabbit, dosed orally, were investigated. Column chromatography yielded five crystalline metabolites which were identified by GLC and spectroscopic measurements. Three of these substances were hydroxylated in the 4α-position and one in the 6a-position with the cyclopropane ring intact. The fifth substance, 17β-hydroxy-3β-methyl-5α-androstan-2-one, can be derived from initial hydroxylation of the cyclopropane ring at C-2 followed by ring opening. The dosed substance and triol material was shown to be present by GLC and m.s. measurements. GLC determinations show that hydroxylation has occurred at C-4?C-6>C-2.     

Incorporation of 5α-furostan-3β,26-diol into tigogenin by digitalis lanata

2,2′,4,4′-³H₄-dihydrotigogenin was converted by Digitalis lanata plants into tigogenin.     

Synthesis, aggregation behavior and cholesterol solubilization studies of 16-epi-pythocholic acid (3α,12α,16β-trihydroxy-5β-cholan-24-oic acid)

Synthesis, aggregation behavior and in vitro cholesterol solubilization studies of 16-epi-pythocholic acid (3α,12α,16β-trihydroxy-5β-cholan-24-oic acid, EPCA) are reported. The synthesis of this unnatural epimer of pythocholic acid (3α,12α,16α-trihydroxy-5β-cholan-24-oic acid, PCA) involves a series of simple and selective chemical transformations with an overall yield of 21% starting from readily available cholic acid (CA). The critical micellar concentration (CMC) of 16-epi-pythocholate in aqueous media was determined using pyrene as a fluorescent probe. In vitro cholesterol solubilization ability was evaluated using anhydrous cholesterol and results were compared with those of other natural di- and trihydroxy bile acids. These studies showed that 16-epi-pythocholic acid (16β-hydroxy-deoxycholic acid) behaves similar to cholic acid (CA) and avicholic acid (3α,7α,16α-trihydroxy-5β-cholan-24-oic acid, ACA) in its aggregation behavior and cholesterol dissolution properties.     

5α,8α-Epidioxysterols from the gorgonian Eunicella cavolini and the ascidian Trididemnum inarmatum: Isolation and evaluation of their antiproliferative activity

Three new (1, 4, 9) and nine previously reported (2, 3, 5-8, 10-12) 5α,8α-epidioxysterols were isolated from the organic extracts of the gorgonian Eunicella cavolini and the ascidian Trididemnum inarmatum. The structures and relative configurations of 1-12 were established on the basis of detailed NMR spectroscopic analyses and comparison with the literature. The growth inhibitory effects of 1-12 were evaluated against MCF-7 human breast cancer cells. Compound 1, bearing a cyclopropyl moiety in the side chain, exhibited the highest antiproliferative activity.     

Synthesis of new steroid haptens for radioimmunoassay. Part III. 15β-carboxyethylmercaptosteroid-bovine serum albumin conjugates. Specific antisera for radioimmunoassay of 5α-dihydrotestosterone, 5α-androstane-3β, 17β-diol and 5α-androstane-3α, 17β-diol

The syntheses of 15β-carboxyethylmercapto-5α-dihydrotestosterone, 15β-carboxy-ethylmercapto-5α-androstane-3β, 17β-diol and 15β-carboxyethylmercapto-5α-androstane-3α, 17β-diol and the preparation of their bovine serum albumin (BSA) conjugates are described. These conjugates were employed for the generation of specific antisera suitable for radioimmunoassay (RIA) of 5α-dihydrotestosterone (5α-DHT), 5α-androstane-3β, 17β-diol (3β3-diol) and 5α-androstane-3α, 17β-diol (3α-diol).     

Opposing actions of the progesterone metabolites, 5α-dihydroprogesterone (5αP) and 3α-dihydroprogesterone (3αHP) on mitosis,apoptosis, and expression of Bcl-2, Bax and p21 in human breast cell lines

Previous studies have shown that breast tissues and breast cell lines convert progesterone (P) to 5α-dihydroprogesterone (5αP) and 3α-dihydroprogesterone (3αHP) and that 3αHP suppresses, whereas 5αP promotes, cell proliferation and detachment. The objectives of the current studies were to determine if the 5αP- and 3αHP-induced changes in cell numbers are due to altered rates of mitosis and/or apoptosis, and if 3αHP and 5αP act on tumorigenic and non-tumorigenic cells, regardless of estrogen (E) and P receptor status. The studies were conducted on tumorigenic (MCF-7, MDA-MB-231, T47D) and non-tumorigenic (MCF-10A) human breast cell lines, employing several methods to assess the effects of the hormones on cell proliferation, mitosis, apoptosis and expression of Bcl-2, Bax and p21. In all four cell lines, 5αP increased, whereas 3αHP decreased cell numbers, [³H]thymidine uptake and mitotic index. Apoptosis was stimulated by 3αHP and suppressed by 5αP. 5αP resulted in increases in Bcl-2/Bax ratio, indicating decreased apoptosis; 3αHP resulted in decreases in Bcl-2/Bax ratio, indicating increased apoptosis. The effects of either 3αHP or 5αP on cell numbers, [³H]thymidine uptake, mitosis, apoptosis, and Bcl-2/Bax ratio, were abrogated when cells were treated simultaneously with both hormones. The expression of p21 was increased by 3αHP, and was unaffected by 5αP. The results provide the first evidence that 5αP stimulates mitosis and suppresses apoptosis, whereas 3αHP inhibits mitosis and stimulates apoptosis. The opposing effects of 5αP and 3αHP were observed in all four breast cell lines examined and the data suggest that all breast cancers (estrogen-responsive and unresponsive) might be suppressed by blocking 5αP formation and/or increasing 3αHP. The findings further support the hypothesis that progesterone metabolites are key regulatory hormones and that changes in their relative concentrations in the breast microenvironment determine whether breast tissues remain normal or become cancerous.