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Query: UMLS:C0338671 (Steroids)
 9,479 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A method for the isolation of 3-ketosteroids based on the positive charge of their oximes is described. The biological extract is filtered through a column of sulphoethyl Sephadex LH-20 (H+). Steroids in the filtrate are converted into oximes and the dried reaction mixture is filtered through a column of diethylaminohydroxypropyl Sephadex LH-20 (OH-) in methanol. After evaporation of the solvent and hydroxylamine, the oximes are taken up by and separated on a column of sulphoethyl Sephadex LH-20 (H+) in methanol. Following elution of other steroids, the oximes of 3-ketosteroids are eluted as a group with methanol-pyridine (20:1, v/v), and are converted into trimethylsilyl ethers. Removal of reagents and further purification of the sample is achieved by rapid filtration through Lipidex 5000 in n-hexane-pyridine-hexamethyldisilazane-dimethoxypropane (97:1:2:10). The derivatives are then analyzed by computerized gas chromatography-mass spectrometry using open-tubular glass capillary columns. Recoveries of picogram amounts of 3H-labelled steroids carried through the entire isolation procedure are 80-90%. The purification achieved in analyses of plasma permits solid injection of the equivalent of 1-2 ml of plasma without overloading of the capillary column. The principle of the isolation procedure might be applicable to other groups of compounds that possess keto or aldehydo groups.
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PMID:Selective liquid chromatographic isolation procedure for gas chromatographic-mass spectrometric analysis of 3-ketosteroids in biological materials. 97 4

Composite microassays for plasma progesterone (P), 17alpha-OH-progesterone (17P), estrone (E1), 17beta-estradiol (E2), and estriol (E3) were developed. Steroids were extracted from plasma samples with diethyl ether, and were separated from each other through two steps of sephadex LH-20 microcolumn chromatography (benzene:methanol 85:15, and n-hexane: benzene: methanol 80:10:10), prior to assays by radioimmunoassay (P, E1, E1, and E3) and competitive protein binding assay (17P). Steroids were recovered satisfactorily through these procedures (mean recovery; P:107.6%, 17P:102.3%, E1:88.2%, E2:84.1%. E3:78.5%). The detectable range for P, 17P, E1, E2, and E3 were 0.01-2 ng/tube, 0.1-10 ng/tube, 10-2000pg/tube, 10-2000 pg/tube, and 0.5-100 ng/tube. The interassay coefficient of variations were less than 10.7%, 15.2%, 17.8%, 11.4%, and 28.1%, respectively. These steroids were measured daily in 4 menstrual cycles from 4 normally menstruating women. Plasma FSH and LH were quantitated previously. The following results were obtained; 1) Plasma P elevated from around LH surge (Day O), and reached a peak on day +5 approximately +7 with the values of 12.74 +/- 2.34 ng/ml (Mean +/- S.D.). 2) Slight decrease in P levels was noted on day +8 approximately +9. 3) A peak in 17P was observed in the preovulatory phase (day -3 approximately -1) with the values of 0.6 approximately 1.3 ng/ml in three of four cases. 4) Changes of 17P during the luteal phase were paralleled to those of P with a peak of 1.16 +/- 0.31 ng/ml on day +5 approximately +7. 5) No remarkable patterns were found in E1 levels throughout the menstrual cycle. 6) A sharp peak in E2 was detected in the preovulatory phase (day -1 approximately 0) with the values of 709.2 +/- 95.9 pg/ml. 7) The second peak of E2 with 378.6 +/- 140.7 pg/ml was observed in the late luteal phase (day +8 approximately +12). 8)E3 was not detected in all samples. The interrelationship between steroids and the correlation with the morphological changes of the ovaries in the normal menstrual cycle are discussed. In the follicular phase, the theca interna cells around the maturing follicle may be growing under the influence of pitiutary gonadotropins to secrete large amounts of 17P and E2, which may possibly affect the pituitary for LH surge, followed by ovulation. In the luteal phase, both the granulosa cells and theca intera cells are luteinized, which may produce and secrete large amount of P, 17P, and E2.
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PMID:[Composite microassays of plasma progesterone, 17alpha-OH-progestrerone, estrone, 17beta-estradiol and estriol in normal adult women. I. Assay methods and steroid patterns in normal menstrual cycle (author's transl)]. 124 48

Simultaneous determination of progesterone, androst-4-enedione, pregnenolone, dehydroepiandrosterone (DHEA) and 17-hydroxyprogesterone has been developed for human cerebral tissue. Before immunoassay, steroids were separated on a Celite column with propylene glycol as stationary phase with hexane containing increasing proportions of dichloromethane as mobile phase. This system allowed separation of steroids of similar polarity, especially of pregnenolone and progesterone. The brain regions studied cortex (prefrontal, parietal and temporal), cerebellum and corpus callosum, were obtained after autopsy from 9 women and 1 man between 76 and 93 years of age. Steroids were found in all regions. The overall concentrations expressed in nmol/kg of tissue were: 10.1, 7.6, 120.7, 19.6 and 10.4 respectively, for progesterone, androst-4-enedione, pregnenolone, dehydroepiandrosterone and 17-hydroxyprogesterone, corresponding to 7.3, 4.9, 74, 6.5 and 9.2 times the plasma levels. These very high concentrations, not previously described in human brain tissue, pose the question of the existence of local biosynthetic pathways independent of the peripheral endocrine gland system as well as that of progressive accumulation of steroids over a lifetime. Concentrations of each steroid in each subject varied little among the various brain regions studied, but there was much variation among the subjects with respect to the concentrations of a given steroid.
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PMID:Simultaneous radioimmunoassay of progesterone, androst-4-enedione, pregnenolone, dehydroepiandrosterone and 17-hydroxyprogesterone in specific regions of human brain. 295 61

The sulfoconjugated steroids estrone sulfate (ES) and dehydroepiandrosterone sulfate (DS) were separated in the reversed phase mode on polyamide-coated TLC plates. Baseline resolution was obtained between tritiated ES and DS standards when run with a mobile phase of 20% acetonitrile in 5mM aqueous triethylamine, triethanolamine, tris-hydroxymethylaminomethane, tributylamine or ammonia. ES and DS showed no mobility in the absence of an ion-pair reagent. The radioactive peaks were detected and integrated non-destructively by scanning. Quantitation was confirmed by elution of cut-out peak areas and liquid scintillation counting. Similar results were obtained with washed ethanol extracts of serum labeled with tritiated ES and DS. The extracts were defatted on the plate with hexane: ethyl acetate (1:1) prior to the reversed phase development.
Steroids
PMID:A new reversed phase, paired ion thin-layer chromatographic method for steroid sulfate separations. 297 81

Propargyl amine was protected by condensing it with 2,5-hexane-dione to give 2,5-dimethyl-N-(2'-propyn-1'-yl)pyrrole (2). The latter was converted to the corresponding Grignard reagent with ethylmagnesium bromide, and then condensed with estrone tetrahydropyranyl ether to give 17 alpha-[3'-(2'',5''-dimethyl-1''-pyrryl)-1'-propyn-1'-yl)-1,3 ,5( 10)- estratriene-3,17 beta-diol 3-tetrahydropyranyl ether (3), in 85% yield. Acetic acid and methanol cleaved the tetrahydropyranyl ether group, and hydroxylamine and sodium bicarbonate cleaved the pyrrole ring to give 17 alpha-(3'-amino-1'-propyn-1'-yl)-1,3,5(10)-estratriene-3,17 beta-diol (1), estrynamine. Several derivatives and analogs of 1 were also synthesized. Estrynamine binds to estrogen receptor with an RBA of 0.0045 (estradiol = 1.0). Several of the compounds, including estrynamine, are weak estrogens (stimulation of prolactin synthesis).
Steroids
PMID:Conjugates of steroids and anti-cancer agents. III. The synthesis of estrynamine and certain derivatives. 344 80

We developed sensitive, specific "high-performance" liquid chromatography (HPLC) for determining suppressed cortisol and corticosterone in human plasma and compared its efficacy with that of conventional radioimmunoassay (RIA) at concentrations in the nanogram per liter range. Steroids from a 0.5-mL aliquot of plasma were extracted by rapid-flow fractionation, with diethyl ether as mobile-phase solvent, diatomaceous earth granules as stationary-support material. Analytical recovery of the steroids approached 100%. Concentrations in plasma were determined from peak-height ratio calibration (dexamethasone internal standard). The analytical column contained silica gel and the solvent system was water/methanol/dichloromethane/n-hexane (0.1/3/30/66.9 by vol). We could measure the steroids before and 20 h after oral administration of 0.5 mg of dexamethasone. The detection limit was 300 ng per liter of plasma for corticosterone, 500 ng/L for cortisol, with CVs of less than 4%. Determining corticosterone after administration of dexamethasone, in four of 20 such samples we could determine concentrations greater than 300 ng/L; the others contained corticosterone between 100 and 300 ng/L, but these values could not be certified analytically. Mean concentrations of these hormones as determined by RIA substantially exceeded those by HPLC. Some cross reactions in RIA could not be considered negligible in spite of pre-column treatment of the extracts.
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PMID:Liquid chromatography and radioimmunoassay compared for determination of cortisol and corticosterone in plasma after a dexamethasone suppression test. 362 64

TLC plates with a 25 mu thick polyamide stationary phase were modified for the separation of neutral steroids by impregnation with propylene glycol. A mixture of tritiated 5 alpha-androstan-3 alpha,17 beta-diol, testosterone, 17 beta-hydroxy-5 alpha-androstan-3-one and 4-androstene-3,17-dione was applied to the plate and developed in a toluene mobile phase to a height of 13.6 cm. This resulted in complete resolution of the 4 compounds as detected by a gas flow scanner or imaging analyzer. Cutting and elution of peak areas with methanol resulted in quantitative recovery of all four steroids. The thinness of the layer also permitted a 3-5% counting efficiency on scanning, resulting in good quantitation of recovery without liquid scintillation counting. The high sorptive capacity of the polyamide layer also enabled extracts of normal human serum to be defatted on the TLC plate by development with pure hexane prior to the toluene step. The new method thus offers several advantages over existing methods for steroid separations and should be adaptable to separations of other relatively non-polar compounds.
Steroids 1985 Jun
PMID:A new partition thin-layer chromatographic method for steroid separations. 383 32

A gas chromatographic-mass spectrometric (GC-MS) method for analysis of unconjugated steroids in a rat testis is described. A combined solvent-solid extraction procedure, utilizing Lipidex 1000 and Sep-Pak C18, gives a 25-fold purified extract. Steroids in this extract are fractionated by straight phase high-performance liquid chromatography (HPLC) on a LiChrosorb DIOL column in n-hexane-2-propanol, 92:8 (v/v). Four fractions are collected and the steroids are converted to tert-butyldimethylsilyl (TBDMS), 3-enol-TBDMS, and mixed TBDMS-trimethylsilyl (TMS) derivatives using TBDMS- and TMS-imidazole with sodium formate as catalyst under conditions suitable for the steroids present in the respective fractions. The derivatives are purified by reversed phase HPLC in 100% methanol and are analyzed by GC-MS, using selected ion monitoring of the major ions of high mass. For quantification, a mixture of known amounts of ten 14C-labelled steroids, [3H]estradiol and [2H3]estradiol are added to the testis homogenate. The mean concentrations (ng/g wet wt) of the twelve steroids determined were: 4-androstene-3, 17-dione, 4.0; testosterone, 127; 17 beta-hydroxy-5 alpha-androstan-3-one, 4.5; 5 alpha-androstane-3 alpha, 17 beta-diol, 5.7; 5 alpha-androstane-3 beta, 17 beta-diol, 1.5; progesterone, 5.5; 17 alpha-hydroxyprogesterone, 14.4; 3 beta-hydroxy-5-androsten-17-one, 0.07; 5-androstene-3 beta, 17 beta-diol, 0.25; 3 beta-hydroxy-5-pregnen-20-one, 10.3; 3 beta, 17 beta-dihydroxy-5-pregnen-20-one, 0.95; and estradiol, 0.025. Variations between animals were large whereas testes from the same animal in most cases had similar steroid concentrations.
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PMID:Analysis of profiles of unconjugated steroids in rat testicular tissue by gas chromatography-mass spectrometry. 406 7

A simple method has been developed using 'SEP-PAK' disposable silica cartridges to separate the major endogenous vitamin D metabolites, namely vitamin D3, 25-hydroxy vitamin D3 (25OHD3), 1,25 dihydroxy vitamin D3 (1.25 (OH)2D3) and 24,25 dihydroxyvitamin D3 (24,25 (OH) 2D3). After extraction of plasma in isopropanol-toluene (25:75) the dried extract is reconstituted in hexane; this is applied to a SEP-PAK column, and stepwise elution carried out under gravity with 0.1 divided by isopropanol in hexane (neutral lipids), 1% isopropanol in hexane (D3), 3 divided by isopropanol in hexane (25OHD3), 3.125 divided by ethanol in dichloromethane (24,25 (OH) 2D3) and 50 divided ethanol in toluene (1, 25(OH) 2D3). Complete separation of these D3 metabolites is achieved by this process and up to 40 samples can be handled at one time. If combined with a suitable ligand binding assay, the system appears to be suitable for preparation of samples prior to the routine assay of vitamin D metabolites.
Steroids 1982 Feb
PMID:A simple method for the isolation of vitamin D metabolites from plasma extracts. 628 Mar 44

Progesterone, estrone, estradiol-17 beta and corticosterone were quantified simultaneously for the first time in female American kestrel (Falco sparverius) plasma. A mean level for each hormone was determined for the laying and non-laying periods of the summer (April-September), and for February. Means were comparable to those of other wild avian species and were significantly higher for the laying period than for the other 2 periods. The mean corticosterone level for February was higher than that for the non-laying summer period. Plasma from laying kestrels, unlike that from other avian species, required lipid removal before column chromatography. Of 2 lipid removal techniques compared, i.e. the cold methanol and hexane:methanol techniques, the latter proved superior.
Steroids 1984 Apr
PMID:Simultaneous quantification of progesterone, estrone, estradiol-17 beta and corticosterone in female American kestrel plasma. 652 50


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