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1.
Lake whitefish, Coregonus clupeaformis, were collected from the Western basin of Lake Erie during spawning. Free and conjugated (sulfated and glucuronidated) steroids including testosterone (T), 11-ketotestosterone (11-kT), estradiol-17beta (E2) and 17,20beta-dihydroxy-4-pregnen-3-one (17,20betaP) were measured in the plasma by radioimmunoassay. In males, the progression of spermiation was characterized by a significant decrease in plasma free steroids, whereas the levels of conjugated steroids remained similar and low, except for sulfated and glucuronidated testosterone. Plasma sex steroids did not correlate with the density or the motility of the spermatozoa. In females, the concentration of plasma T was significantly higher in preovulating than in ovulating females. The levels of E2 and 17,20betaP in ovulating lake whitefish exhibited large variations ranging from below detection limit to 0.9 ng ml(-1) and from 0.2 to 13 ng ml(-1), respectively. Analysis of conjugated steroids revealed high levels of glucuronidated and sulfated 17,20betaP and glucuronidated T in females ovulating in December. However, no significant differences in the proportion of the conjugated steroids were observed.  相似文献   

2.
Choi MH  Kim KR  Chung BC 《Steroids》2000,65(1):54-59
An efficient procedure is described for the simultaneous determination of 9 androgen glucuronides including androsterone, etiocholanolone, 11-ketoandrosterone, 11-ketoetiocholanolone, 11beta-hydroxyandrosterone, 11beta-hydroxyetiocholanolone, and dehydroepiandrosterone (DHEA) in 3-glucuronide form and dihydrotestosterone (DHT) and testosterone in 17-glucuronide form from urine specimens. The method involves solid-phase extraction of the urinary steroids using Serdolit PAD-1 resin, with subsequent conversion to methyl ester-trimethylsilyl (Me-TMS) ether derivatives for the direct analysis by gas chromatography-mass spectrometry (GC-MS) using high temperature MXT-1 (Silcosteel-treated stainless steel) capillary column. Upon split injection of Me-TMS steroids at 330 degrees C into the MXT-1 capillary column initially maintained at 300 degrees C then programmed to 322 degrees C at 2 degrees C/min, each androgen glucuronide was well separated in excellent peak shape. The characteristic ions at m/z 217 constituting the base peaks in the electron-impact (20 eV) mass spectra for most steroids permitted their sensitive detection by GC-MS with selected-ion monitoring (SIM), whereas base peak ion at m/z 271 was used for the SIM of dehydroepiandrosterone-3-glucuronide. The detection limits for SIM of most of the steroids were 15 pg except for the 3-glucuronides of 11-ketoandrosterone and 11-ketoetiocholanolone, which could be detected down to 20 pg. The SIM responses were linear with correlation coefficients varying from 0.981 to 0.993 in the concentration range of 20 to 3000 ng/ml for the androgens studied. When applied to urine samples, the present method allowed rapid screening for the 7 androgens in their glucuro-conjugated forms simultaneously with good overall precision and accuracy within the normal concentration ranges of 15.1 to 3124.6 ng/ml.  相似文献   

3.
Gas chromatography-mass spectrometry (GC-MS) is the method of choice for separation and detection of anabolic steroids in urine. Recently, there have been advances in the areas of gas chromatography columns, tandem mass spectrometry using ion traps, and large volume sample injection that have promise for lowering detection limits and extending the utility of GC-MS for steroid analysis. In this work, a Varian Saturn III GC-MS system has been used in its tandem mass spectrometry mode to detect low picogram levels of model steroids in standard solution and the urine matrix. Application of MS-MS-MS provided structurally informative spectra for 3′-hydroxystanozolol at concentrations of 1 ng/ml. In addition, four polysilphenylene-polydimethylsiloxane capillary columns were examined for background and selectivity. The columns had bleed several-fold lower than conventional polysiloxane columns. The columns also exhibited significant differences in selectivity for structurally similar steroids. Finally, a new temperature-programmed split-splitless injector was used to inject as much as 25 μl on column. The resulting limits of detection were 5 pg/ml for norandrosterone.  相似文献   

4.
The aim of this study was to develop a method for comprehensive profiling of metabolites involved in mammalian steroid metabolism. The study was performed using the partial filling micellar electrokinetic chromatography (PF-MEKC) technique for determination of endogenous low-hydrophilic steroids. The detection techniques in capillary electrophoresis were UV absorption and electrospray mass spectrometry (ESI-MS). Thirteen steroids were included in the method development, and the selected were metabolites involved in major pathways of steroid biosynthesis. Although only eight of them could be separated and detected with UV, they could be identified by ESI-MS using selected ion monitoring (SIM) technique. Tandem MS spectra were also collected. UV detection was more sensitive than MS due to better separation of compounds and the selective signal sensitivity. The lowest limits of detection were 10-100ng/mL for cortisone, corticosterone, hydrocortisone and testosterone. The other steroids could be detected at 500-1000ng/mL. The identification of cortisone, corticosterone, hydrocortisone, estrogen and testosterone were made in patient urine samples and their concentrations were 1-40mug/L.  相似文献   

5.
A selective and extremely sensitive procedure has been developed and optimized, using high-performance liquid chromatography (HPLC), specific derivatization and gas chromatography–mass spectrometry (GC–MS), to simultaneously quantify very small amounts of different neurosteroids from rat brain. Unconjugated and sulfated steroids in brain extracts were separated by solid-phase extraction. The unconjugated fraction was further purified by HPLC, the steroids being collected in a single fraction, and the sulfated fraction was solvolyzed. All steroids were derivatized with heptafluorobutyric acid anhydride and analyzed by GC–MS (electron impact ionization) using selected-ion monitoring. High sensitivity and accuracy were obtained for all steroids. The detection limits were 1 pg for pregnenolone (PREG), dehydroepiandrosterone (DHEA) and their sulfate esters PREG-S and DHEA-S, 2 pg for progesterone (PROG) and 5 pg for 3α,5α-tetrahydroprogesterone (3α,5α-THP). In a pilot study on a rat brain, the concentrations of PREG-S and DHEA-S were 8.26±0.80 and 2.47±0.27 ng/g, respectively. Those of PREG, DHEA and PROG were 4.17±0.22, 0.45±0.02 and 1.95±0.10 ng/g, respectively. Good linearity and accuracy were observed for each steroid. The methodology validated here, allows femtomoles of neurosteroids, including the sulfates, found in small brain samples (at least equal to 10 mg) to be quantified simultaneously.  相似文献   

6.
A sensitive, specific, and reproducible high-performance liquid chromatographic assay for the simultaneous determination of prednisone, prednisolone and cortisol in biological fluids was developed with dexamethasone as the internal standard. Samples are extracted with methylene chloride, washed with sodium hydroxide and then water, and chromatographed on a microparticulate silica gel column with UV detection at 254 nm. Sensitivity was greater than 15 ng for all four steroids. Specificity was supported by use of dual wavelength UV detection and/or radioimmunoassay. The assay has been applied in pharmacokinetic studies and a typical plasma concentration—time profile for the three steroids is presented for one subject who received 50 mg of prednisone.  相似文献   

7.
A qualitative liquid chromatography-electrospray ionization tandem mass spectrometry method was developed for screening of the abuse of 4-chlorodehydromethyltestosterone, danazol, fluoxymesterone, formebolone, metandienone, oxandrolone, and stanozolol. The introduced method measures simultaneously nine different 17-alkyl-substituted anabolic androgenic steroids or their unconjugated metabolites in human urine, using methyltestosterone as an internal standard. Sample preparation involved one-step liquid extraction. Liquid chromatographic separation was achieved on a reversed-phase column with methanol-water gradient containing 5 mmol/l ammonium acetate and 0.01% (v/v) acetic acid. Compounds were ionized in the positive mode and detected by multiple reaction monitoring. All steroids within the study could be selectively detected in urine with detection limits of 0.1-2.0 ng/ml. The method showed good linearity up to 250 ng/ml with correlation coefficients higher than 0.9947. With simple and fast sample preparation, low limits of detection, and high selectivity and precision, the developed method provides advantages over the present testing methods and has the potential for routine qualitative screening method of unconjugated 17-alkyl-substituted anabolic steroids in human urine.  相似文献   

8.
A rapid high-performance liquid chromatographic (HPLC) method for the simultaneous determination of cortisol and cortisone in a single extract of 1 ml of serum is described. The method employs meprednisone as the internal standard. The steroids were analysed isocratically by reversed-phase HPLC with an octadecylsilane-bonded (ODS) column using ultraviolet detection. The matrix effect was reduced by lowering the sample pH by adding glacial acetic acid to the sera. The samples were then filtered through regenerated cellulose membranes at 4°C and extracted with diethyl ether. The dried eluates were redissolved in the mobile phase and injected into the column. The detection limit of the assay for both steroids was 500 ng/l. Cortisol was determined in twenty serum samples by both HPLC and radioimmunoassay (RIA). The results were similar. Interference by other steroids and certain steroid analogue drugs was also studied. The HPLC method yielded no cross-reactivity between the different steroids as may occur with the RIA technique. The HPLC method was technically easy to perform and it allowed us to quantify both cortisol and cortisone in a single serum extract with high specificity.  相似文献   

9.
Steroidogenesis in immature porcine Leydig cells was investigated in primary culture at 48-84 h under basal conditions and in the presence of hCG. The basal accumulation of unconjugated steroids was close to linear only during the first 4 h of study, whereas the sulphate-conjugated steroids accumulated essentially linearly over the 36 h experimental period. At the last time point, 95% of the steroids measured were sulphated. Stimulation with hCG (1 ng/ml) led to a still more pronounced sulphate conjugation, and approx 99% of the steroids measured were sulphated at 36 h. Under maximal stimulation with hCG (100 ng/ml) the sulphates accounted for 74% of the total steroids measured at 36 h. Testosterone, androstenedione, dehydroepiandrosterone, 5-androstene-3 beta, 17 beta-diol and estrone were usually quantitatively the most important unconjugated steroids, and sulphated dehydroepiandrosterone, estrone, testosterone and 5-androstene-3 beta, 17 beta-diol were the most important steroid sulphates, especially following maximal stimulation of the cultures. These data emphasize the importance of steroid sulphates in porcine testicular steroid metabolism. Under stimulation with hCG, there was a rapid response in testicular steroidogenesis, initially seen as a rapid increase in the secretion of unconjugated and sulphated steroids. At approx 4-12 h, the rate of sulphate conjugation appeared to reach or even to exceed that of steroid biosynthesis, which lead to stabilisation or a decrease in the concentrations of unconjugated steroids. Only high doses of hCG, 10-100 ng/ml, were then able to lead to a net accumulation of unconjugated steroids, at 24-36 h of incubation with hCG.  相似文献   

10.
The regulation of the production of steroids and steroid sulfates and the activity of aromatase in human luteinized granulosa cells were investigated. The cells were cultured for 48 h in the presence or absence of hCG and FSH. Basal production of pregnenolone (Pre, 0.3 +/- 0.03 ng/micrograms protein) and progesterone (P, 19.3 +/- 1.7 ng/micrograms protein) were high compared with that of other steroids beyond P in the steroidogenic pathway. The concentration of 17 alpha-hydroxyprogesterone (17-OHP) was lower 0.17 +/- 0.06 ng/micrograms and that of other steroids in the 4-ene and 5-ene pathways and steroid sulfates less than 0.05 ng/micrograms. Both hCG and FSH (100 ng/ml) stimulated the production of Pre and P 3- to 5-fold, but only minimal stimulation of other steroids and steroid sulfates was observed. Aromatase activity of granulosa-luteal cells was measured from the rate of formation of 3H2O from 1 beta-[3H]androstenedione (1 beta[3H]A) after exposing the cells to hCG, FSH or estradiol (E2) for 48 h. Basal aromatase activity was relatively low, but hCG and FSH stimulated aromatase 8- and 4-fold, respectively. The incubation of granulosa-luteal cells with E2 did not affect basal aromatase activity, but E2 augmented FSH-stimulated aromatase 1.4-fold (P less than 0.025). The results suggest that there is low 17 alpha-hydroxylase and steroid sulfokinase activity in human granulosa-luteal cells. Aromatase activity in these cells is regulated by both hCG and FSH, and intra-ovarian estrogens may regulate granulosa cell aromatase activity.  相似文献   

11.
Human semen was examined for the presence of 16-androstenols, 16-androstenones and androgens. Extracts were analysed by gas chromatography-mass spectrometry after derivatization of steroids under study. In a qualitative study, 5 alpha-androst-16-en-3 alpha- and 3 beta-ols, 5,16-androstadien-3 beta-ol and 5 alpha-androstan-3 beta-ol were detected in a semen pool A. Hydroxyl groups were converted to tert-butyldimethylsilyl ethers, the ions selected for monitoring being [M-57]+, consistent with loss of the tert-butyl group. For a more detailed quantitative study, a second semen pool B was used. In this case, all hydroxyl groups were converted to trimethylsilyl ethers, while oxo groups were not derivatized. As with semen pool A, separation of steroids was achieved using capillary gas chromatography with appropriate temperature programming. Quantification was carried out by mass spectrometry using selected ion monitoring of two significant ions and appropriate internal standards. The following steroids were identified at the concentrations indicated: 5 alpha-androst-16-en-3 alpha- and 3 beta-ols and 5,16-androstadien-3 beta-ol (concentration range, 0.5-0.7 ng/ml). 5 alpha-Androst-16-en-3-one and 4,16-androstadien-3-one were also present at levels of 0.7-0.9 ng/ml. Two androgens, testosterone and 5 alpha-dihydrotestosterone were found at concentrations of 0.5 and 0.3 ng/ml, respectively. These data, showing the presence of 16-androstenes and androgens in human semen, appear to be consistent with testicular formation of these steroids. The possible significance of the odorous 16-androstenes is discussed.  相似文献   

12.
This study was carried out qualitatively and quantitatively to investigate the presence and the concentrations of anabolic steroids in urine collected from orally administered humans. Microanalysis of conjugated steroids by gas chromatography and mass spectrometry (GC/MS) has been carried out. Following oral administration three major metabolites of anabolic steroid drugs have been detected and partially characterized. The six steroids can be analysed at the same time in 17 min. The lower detection limit was 10 ng/ml in 5 ml of urine. The conjugated steroids from urine were centrifuged to 2,430g for 10 min, the supernatant solution passed through Amberlite XAD-2 column and the steroids eluted fraction esterified by using MSTFA and TMSI. The rate of metabolism and urinary excretion seem to be reasonably fast.  相似文献   

13.
Adrenal steroid profiling, including 17α-OH progesterone (17OHP), 11-deoxycortisol (S), Δ4-androstenedione (Δ4-A) and cortisol (F) in blood spots by tandem mass spectrometry, is used for newborn screening to detect congenital adrenal hyperplasia (CAH). Pre-analytical sample processing is critical for assay specificity and accuracy; however, it is laborious and time-consuming. This study describes the development and validation of a new Liquid Chromatography-Tandem Mass Spectrometry (LC-MS/MS) method for the simultaneous quantification of five steroids: 17OHP, S, Δ4-A, F and cortisone (E) in blood spots from newborns. Whole blood was eluted from a 5.00 mm dried blood spot by an aqueous solution containing the deuterium-labeled internal standards d8-17OHP and d4-cortisol. The steroids extracted from blood spot into aqueous solution were subsequently purified via Extelut mini NT1 column using diethylether. The extracts were evaporated and quantified using LC-MS/MS. The detection limit was 0.25 ng/mL for 17OHP and S, 0.4 ng/mL for Δ4-A and 0.5 ng/mL for F and E. The limit of quantification was 0.5 ng/mL for 17OHP, S and Δ4-A and 1 ng/mL for F and E. Precision for 17OHP, S, Δ4-A at concentrations of 0.5, 2, and 8 ng/mL (n=5) in fortified steroid free serum samples was 1.3-3.5% (intra-assay CV) and 7-14.8% (inter-assay CV). Precision for F and E at concentrations of 5 and 20 ng/mL was 1.5-4.8% (intra-assay, CV%) and 6-15% (inter-assay, CV%). Accuracy was calculated at concentrations of 0.5, 2, and 8 ng/mL for 17OHP, S and Δ4-A and ranged from -0.3 to 0.2%, while for F and E it ranged from -3.2 to 0.2%. Relative recoveries at concentration 2 ng/mL and 8 ng/mL for 17OHP, S, Δ4-A and at 5 ng/mL and 20 ng/mL for F and E ranged from 55% to 80%. Reference intervals were estimated for all steroids in newborns (on day 3). The steroid profile assay herein described is sensitive, specific and accurate and involves a simple pre-analytical sample manipulation; it is therefore suitable for routine analysis and provides data for samples within normal range as well as those with elevated levels. For the first time to our knowledge, cortisone levels are reported in dried blood spots from newborns.  相似文献   

14.
A highly sensitive and specific method has been developed for the simultaneous measurement of free (unconjugated) or sulfate-conjugated forms of dehydroepiandrosterone (DHEA), 7alpha-hydroxy-DHEA (7alpha-OH-DHEA), 7beta-hydroxy-DHEA (7beta-OH-DHEA), and 7-oxo-DHEA (7-oxo-DHEA) in human serum. This method is based upon a stable isotope-dilution technique by gas chromatography-selected-ion monitoring mass spectrometry. Free steroids were extracted from serum with an organic solvent and the sulfate-conjugated steroids remained in aqueous phase. Free steroids were purified by solid-phase extraction, while sulfate-conjugated steroids were hydrolyzed by sulfatase and deconjugated steroids were purified by solid-phase extractions. The extracts were treated with O-methylhydroxylamine hydrochloride and were subsequently dimethylisopropylsilylated. The resulting methyloxime-dimethylisopropylsilyl (MO-DMIPS) ether derivatives were quantified by gas chromatography-selected-ion monitoring mass spectrometry in a high-resolution mode. The detection limits of MO-DMIPS ether derivatives of DHEA, 7alpha-OH-DHEA, 7beta-OH-DHEA and 7-oxo-DHEA were 1.0, 0.5, 0.5 and 2.0pg, respectively. Coefficients of variation between samples ranged from 10.6 to 22.9% for free 7-oxygenated DHEA to less than 10% for DHEA and sulfate-conjugated 7-oxygenated DHEA. The concentrations of these steroids were measured in 18 sera samples from healthy volunteers (9 males and 9 females; aged 23-78 years). Free DHEA, 7alpha-OH-DHEA, 7beta-OH-DHEA and 7-oxo-DHEA levels ranged between 0.21-3.55, 0.001-0.194, 0.003-0.481, and 0.000-0.077ng/ml, respectively, and the sulfate-conjugated steroid levels of these metabolites ranged between 253-4681, 0.082-3.001, 0.008-0.903, and 0.107-0.803ng/ml, respectively. The free DHEA-related steroid concentrations were much lower than those previously measured by RIA and low-resolution GC-MS. The present method made it possible to determine simultaneously serum DHEA-related steroid levels with sufficient sensitivity and accuracy.  相似文献   

15.
In the present paper we report the LC-MS/MS determination of residues of 12 anabolic steroids in bovine serum, as an expansion of our work protocols for steroids determination in biological matrices. Steroids analyzed included α-zearalanol, β-zearalanol, α-trenbolone, β-trenbolone, methyltestosterone, α-estradiol, β-estradiol, ethynylestradiol, α-boldenone, β-boldenone, α-nortestosterone and β-nortestosterone. Following protein precipitation, serum samples were cleaned up by solid-phase extraction using Oasis HLB and Amino cartridges. Atmospheric pressure chemical ionization (APCI) in both positive and negative ionization modes was used and mass spectrometry detection was carried out in multiple reaction monitoring mode following two or (in most cases) three product ions per precursor ion. The method was validated in accordance with the Commission Decision 2002/657/EC. The decision limit (CCα) values obtained, ranged from 0.01 to 0.07 ng/ml and the detection capability (CCβ) values obtained ranged from 0.02 to 0.12 ng/ml. The recoveries ranged from 70.2% to 118.2%. The developed method is suitable for routine and confirmatory purposes such as control of illegal use in livestock production.  相似文献   

16.
Zhao M  Baker SD  Yan X  Zhao Y  Wright WW  Zirkin BR  Jarow JP 《Steroids》2004,69(11-12):721-726
A rapid, sensitive, and specific method using liquid chromatography tandem mass spectrometry (LC/MS/MS) has been developed for simultaneous determination of testosterone (T), dihydrotestosterone (DHT), estradiol (E2), and 5alpha-androstan-3alpha, -17beta-diol (3alpha-Diol) within human testicular fluid. Sample pretreatment involved a one-step extraction with diethyl ether. The analytes were separated on a Waters X-Terra C18 (150 mm x 2.1 mm i.d., 3.5 microm) analytical column with acetonitrile/water mobile phase (70:30, v/v) containing 0.1% formic acid using isocratic flow at 0.15 ml/min for 8 min. The column effluent was monitored by tandem mass spectrometry with electrospray positive ionization. Linear calibration curves were generated over the range of 0.1-50 ng/ml for T, 0.02-1 ng/ml for DHT, 0.05-2 ng/ml for E2, and 0.2-10 ng/ml for 3alpha-Diol, with values for the coefficient of determination of >0.99. The overall extraction efficiency was greater than 86% for T, 75% for DHT, 66% for E2, and 60% for 3alpha-Diol. The values for within-day and between-day precision and accuracy were <15%. We measured each of the four steroids in testicular sample volumes of only 20 microl, obtained by percutaneous testicular aspiration. The mean intratesticular testosterone concentration found by LC/MS/MS, 572 +/- 102 ng/ml, was similar to that previously obtained by radioimmunoassay (RIA). The mean intratesticular estradiol concentration was 15.7 +/- 2.3 ng/ml, which also correlated well with RIA measurement. Both DHT and 3alpha-Diol were below the limits of detection by RIA, but could be measured accurately by LC/MS/MS. In conclusion, LC/MS/MS represents a sensitive and accurate means by which to measure four separate steroids within small volume samples of testicular fluid.  相似文献   

17.
We describe a simple enzymatic method for the sensitive and specific detection and quantitation of families of hydroxy- and oxo-steroids in biological mixtures. Analysis of the profiles of individual steroids may be achieved following their chromatographic separation. The objectives of this analytical system are, therefore, different from conventional methods which are designed to measure single steroids with a high degree of specificity. The method employs highly purified and active bacterial hydroxysteroid dehydrogenases (HSD) which promote stereospecific, nicotinamide nucleotide-dependent oxidations and reductions at specified positions of steroids. In the presence of catalytic quantities of steroids these enzymes promote the transfer of hydrogen (transhydrogenation) between NADH and NAD analogues. A recently purified 17 beta-HSD from an Alcaligenes species (D. W. Payne and P. Talalay, J. biol. Chem., 260, 13468-13655, 1985) shows almost complete specificity for the 17 beta-hydroxy- and 17-oxo-groups of both C18 and C19 steroids. This enzyme catalyzes steroid-dependent transhydrogenation between NADH and the thionicotinamide analogue of NAD (S-NAD). When these components are incubated at pH 8.5 in the presence of minute quantities of steroid substrates, S-NADH (measured at 398 nm where NADH does not absorb) accumulates at a constant rate which is proportional to the concentrations of steroid and enzyme. The linear increase in absorbance with time is a measure of the total concentration of 17 beta-hydroxy- and 17-oxo-steroids, and can be used to detect subpicomol quantities of steroids. The method is illustrated by the detection and identification of free and conjugated androgens in human serum following their separation by high pressure liquid chromatography. The specificity of the transhydrogenase assay is completely dependent on the specificity of the enzyme and is thus applicable to the detection of other hydroxy- and oxo-steroids by making use of HSDs with appropriate specificities (e.g. 3 alpha-HSD for the measurement of 3 alpha-hydroxy- and 3-oxo-steroids). The simple one-step reaction lends itself to automation, needs no auxiliary detection systems, and requires only an inexpensive colorimeter.  相似文献   

18.
The concentrations of 16 alpha-hydroxydehydroepi-androsterone sulfate (16 alpha-OHDHAS) and androst-5-ene-3 beta, 16 alpha-, 17 beta-triol-3-sulfate (A-TriolS) were measured in the plasma and breast cyst fluid (BCF) of women with gross cystic disease of the breast. In the 19 BCF samples analyzed, the 16 alpha-OHDHAS and A-TriolS concentrations ranged from 15 to 1130 ng/mL, and 12 to 871 ng/mL, respectively. However the concentrations of these steroids in the sera of these women were lower (15-179 ng/mL, 8-80 ng/mL, respectively). Estriol-3-sulfate (E3-3S) concentrations in the BCF samples ranged from barely detectable (0.2 ng/mL) to 3 micrograms/mL. In BCF or serum a positive linear correlation was observed in the concentration of 16 alpha-OHDHAS and A-TriolS (p less than 0.001 and 0.05, respectively). However, in the same patients no statistical significance was observed in the BCF vs serum concentrations of these two steroids. When the specimens from this and previous studies were combined, positive correlation was found between potassium ion concentration and E3-3S or 16 alpha-OHDHAS. The origin of the high concentration of E3-3S is still obscure. Although no linear correlation between 16 alpha-OHDHAS and E3-3S was observed, the possibility of a precursor-product relationship between the two is not elimnated.  相似文献   

19.
Recently the use of high resolution mass spectrometry or tandem mass spectrometry has enabled the detection of low amounts of anabolic steroids. As a consequence, the post-administration detection time of these drugs has been extended. Recent investigations have shown that norandrosterone, previously unequivocally regarded as evidence of nandrolone administration, might be an endogenous steroid present in small amounts in urine of humans. In this study, very low concentrations (<1 ng/ml) of norandrosterone in urine of a female athlete were detected using tandem mass spectrometry. The presence of norandrosterone was strongly correlated with high plasma 17beta-estradiol levels during the menstrual cycle. Analysis of urine samples from pregnant women supports the hypothesis of formation of precursors for urinary 19-norandrosterone during aromatization of androgens to estrogens. The detection of low urinary concentrations of norandrosterone (0.2-0.5 ng/ml) in samples after strenuous exercise could be regarded as an additional evidence for the existence of such a pathway.  相似文献   

20.
M F Pichon  E Milgrom 《Steroids》1973,21(3):335-346
A competitive protein binding assay for the measurement of progesterone in human plasma without chromatographic separation of steroids and recovery evaluation in individual samples is described. It is based on the specificity of the progesterone binding plasma protein (PBP) of the pregnant guinea pig. A dried petroleum ether extract of plasma was incubated with 3H-progesterone and 1600 fold diluted pregnant guinea pig plasma. Bound radioactivity was measured with a dextran coated charcoal suspension technique. Plasma progesterone concentration was obtained by comparison with a standard curve and correction for extraction separately measured for each batch of petroleum ether. The sensitivity was 100 pg. Recovery experiments for progesterone and competing steroids added to plasma respectively showed the accuracy and the specificity of the method. However comparison of the results from assays with and without chromatographic separation of steroids, showed that in the latter-case the specificity was good only for plasmas containing more than 1ng/ml of progesterone. Concentration of progesterone in plasma from men was 0.46±0.14 ng/ml (mean ± S.D) and from post menopausal women 0.30± 0.13 ng/ml.Between days 1 and 13 and days 16 and 22 of the normal menstrualcycle the concentrations were respectively 0.81 ± 0.38 and 12.50 ± 2.96 ng/ml. The variations of the progesterone concentration during pregnancy are also shown.  相似文献   

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