Citations
All
Search in:AllTitleAbstractAuthor name
Publications
(495)
Patents
Grants
Pathways
Clinical trials
Publication
Journal: Journal of Chromatographic Science
January/22/2006
Abstract
A heterogeneous group of 10 male and 15 female judo players are utilized in this study. The subjects complete a standardized maximal treadmill exercise test. Urine samples are collected at the pre- and postexercise stages. The urine steroids are measured using a gas chromatography-mass spectrometry instrument. In rest and after exercise, significantly higher testosterone and epitestosterone concentrations in males (p < 0.01) are found. The etiocholanolone-dehydroepiandrosterone (DHEA) ratio is significantly lower in males than females (p < 0.05). In both males and females, etiocholanolone concentration significantly decreases with the effect of exercise (p < 0.05). 11-OH etiocholanolone concentration also significantly decreases, but only in females (p < 0.05). Positive correlation is found between the changes of the etiocholanolone and epitestosterone concentration caused by exercise.
Publication
Journal: Journal of Steroid Biochemistry and Molecular Biology
May/26/2014
Abstract
Non-steroidal drugs that increase endogenous testosterone (T) may be used to exploit ergogenic effects of androgens in power sports. While superactive GnRH analog use is suspected, neither screening nor detection tests are developed. This study aimed to determine if (a) stimulation for 5 days by leuprolide (a superactive GnRH analog) of serum and urine steroids and urine LH is reproducible at a 2 week interval, (b) nandrolone decanoate (ND) co-administration masks responses to leuprolide administration, (c) performance of urine measurement of leuprolide and M1, its major metabolite, as a detection test. Healthy men were randomized into a 4 week parallel group, open label clinical study in which all men had daily sc injections of leuprolide (1mg) for 4 days in the 1st and 3rd weeks with hormone-free 2nd and 4th weeks. In the 3rd week, men were randomized to either ND injections or no extra treatment. Serum steroids were determined by liquid chromatography, tandem mass spectrometry (LC-MS), urine steroids by gas chromatography, mass spectrometry (GC-MS), urine leuprolide and M1 by high resolution LC-MS and urine LH by immunoassay. Leuprolide stimulated striking, reproducible increases in serum and urine LH and steroids (serum T, dihydroT (DHT), 3α diol; urine T, epitestosterone (E) and androsterone (A). ND suppressed basal serum T, E2, 3α diol, and urinary E but did not mask or change the magnitude of responses to leuprolide. Urine leuprolide and M1 measurement had 100% sensitivity and specificity in detecting leuprolide administration up to one day after cessation of injections with the detection window between 1 and 3 days after last dose. Screening using urine steroid and LH measurements, optimally by urinary log10(LHxT), correctly classified 82% of urine samples. It is concluded that leuprolide stimulation of endogenous testosterone is reproducible after a 10-day interval, is not masked by ND and is reliably detected by urine leuprolide or M1 measurement for at least 1 day after administration.
Publication
Journal: Endokrinologie
June/3/1970
Publication
Journal: Hoppe-Seyler's Zeitschrift fur physiologische Chemie
September/5/1968
Publication
Journal: Endokrinologie
June/28/1969
Publication
Journal: Folia endocrinologica
January/11/1968
Publication
Journal: Drug Testing and Analysis
September/27/2016
Abstract
This study investigated the effect of Ramadan on the haematological and steroid module of the Athletes Biological Passport (ABP) of the World Anti-Doping Agency (WADA). Nine healthy physically active subjects were tested in the morning and afternoon for two days before and three days during Ramadan. Sample collection and all analyses were performed according to WADA technical documents. Although there were significant changes in the haemoglobin concentration during Ramadan, especially during the first fasting week, none of the subjects in this study exceeded the individually calculated thresholds of the ABP. No significant effects on testosterone/epitestosterone (T/E) ratio were observed but only the afternoon specific gravity (SG) of the urine was elevated. Thus, when urinary steroid concentrations are required, SG corrections need to be performed. The haematological and the steroid module of the ABP can be reliably applied during Ramadan as the observed changes are only marginal.
Publication
Journal: Biomedical Chromatography
June/8/2009
Abstract
Capillary electrophoresis-electrospray tandem mass spectrometry (CE-ESI/MS/MS) is a simple and highly sensitive method for quantifying seven urinary androgen glucuronides. The urine samples were diluted and filtered through a membrane filter, and the filtrate was injected into a CE-MS/MS system without further sample preparation steps such as extraction and derivatization. The calibration ranges were 0.01-5 microg/mL for glucuronides of androsterone and 11beta-OHAn-3G, and 5-500 ng/mL for glucuronides of 11-ketoAn, DHEA, testosterone, epitestosterone and DHT. The linearity of the method was 0.992-0.998, and the limits-of-detection at a signal-to-noise ratio of 3 were 5-10 ng/mL. The coefficients of variation were in the range of 4.0-9.0% for intra-day assay and 4.1-9.8% for inter-day assay. The proposed method may be applicable to metabolic profiling in both quantitative and qualitative analysis.
Publication
Journal: Drug Testing and Analysis
April/3/2017
Abstract
Testosterone (T) misuse still represents a major problem in sports drug testing. Many strategies have been developed and applied to routine doping controls in recent years to enable both to identify suspicious samples in initial testing procedures and to confirm the exogenous origin of urinary T by means of carbon isotope ratio (CIR) determinations. Depending on the tested individual's genotype of UGT2B17, significantly different amounts of T are glucuronidated and excreted, which results in unaffected T/epitestosterone ratios after T misuse in those subjects with the deletion/deletion polymorphism (del/del). The aim of this study was to investigate differences in metabolic pathways of orally administered T between persons of del/del and insertion/insertion (ins/ins) genetic polymorphism. Therefore, a recently established method using hydrogen isotope ratios together with high-resolution and high-accuracy mass spectrometry was applied after administration of deuterated T to n = 4 subjects including both genotypes. Participants collected urine specimens directly before and for up to 8 days after the application. Urine aliquots were prepared to yield unconjugated, glucuronidated, and sulphoconjugated fractions of urinary steroids. Besides the significant difference in the excretion of T-glucuronide, all measured metabolites varied rather on an individual basis than due to a genotype difference. New T metabolites (both methylated and de-methylated) were detected and investigated regarding their potential to enhance the screening for T misuse. Sulphoconjugated epiandrosterone was further identified as the biomarker allowing for a prolonged retrospective detection of T misuse by means of CIR determinations for up to 5 days compared to 1 day if currently applied sports drug testing procedures were used. Copyright © 2016 John Wiley & Sons, Ltd.
Publication
Journal: Drug Testing and Analysis
August/1/2017
Abstract
Endogenous steroid use can increase urinary testosterone/epitestosterone (T/E) values. In addition, ethanol in amounts >0.5 g per kg of body weight (g/kg) can also increase T/E values. However, the effect of smaller doses of ethanol on T/E values is unknown. The influence of 0.2 and 0.4 g/kg of ethanol on baseline T/E values in 20 men and 20 women with low and high baseline T/E values was investigated and correlated with ethyl glucuronide (EtG) and ethyl sulfate (EtS) concentrations. T/E values for 7 of the women were excluded from the study because of undetectable T concentrations or for other reasons. One man and 1 woman with a high T/E baseline value had a significant increase in their T/E value after ingestion of 0.2 g/kg of ethanol. One man and 2 women with a high T/E baseline, and 1 woman with a low T/E baseline had significantly increased T/E values after ingestion of 0.4 g/kg of ethanol. There was wide variability in peak EtG concentrations and a lack of correlation between ethanol dose and EtG concentrations. Interestingly, 1 man and 2 women with increased T/E values following ethanol ingestion had EtG concentrations below the World Anti-Doping Agency (WADA) cut-off of 5000 ng/mL. These findings demonstrate that small amounts of ethanol can elevate T/E values, with women being more susceptible. In addition, consideration should be given to the lowering of the WADA EtG cut-off to detect samples with elevated T/E values from ingestion of low doses of ethanol.
Publication
Journal: Steroids
December/3/2018
Abstract
This article studies the genetic influence of polymorphism of the UGT2B17 gen on the urinary steroid profile and its implications for the anti-doping field. The study presents the results of a triple-blind randomized placebo-controlled crossover trial with healthy athletes submitted to a single dose of 250 mg of testosterone cypionate. Forty urine samples were collected from each participant. Mass spectrometry-based techniques commonly used in Anti-Doping laboratories, were employed to measure the urinary concentration and the Δδ13C values of a selection of target compounds for testosterone (T) administration together with LH. Twelve volunteers were included in the study; the polymorphism was evenly distributed among them. After T administration, the most meaningful change affected the Testosterone/Epitestosterone ratio (T/E) and the urinary concentration of LH. In relation with T/E, the wild type homozygous (ins/ins) group there was a mean relative increase of 30 (CI 95%: 25.2 to 36.7); in the heterozygous mutant (del/ins) group it was 19.8 (CI 95%:15.9 to 24.7); and in the homozygous mutant (del/del) group it was 19.7 (CI 95% 14.9 to 26.2). In the case of LH, it́s observed how LH values decrease significantly after the administration of Testex homogeneously among the three groups. The main outcome was related to the (del/del) group (homozygous mutant), where due to the depressed basal level of the steroid profile, if the longitudinal steroid profile of the athlete was not available, the analysis by GC/MS would not produce an "atypical" result according to the WADA TD2016EAAS despite the T administration. However, the genotyping of the UGT2B17 polymorphism, the follow up of LH and the use of GC-C-IRMS makes it possible to identify most of these samples as Adverse.
Publication
Journal: Drug Testing and Analysis
April/1/2019
Abstract
The introduction of alternative markers to the steroid profile can be an effective approach to improving the screening capabilities for the detection of testosterone (T) misuse. In this work, endogenous steroid sulfates were evaluated as potential markers to detect intramuscular (IM) T administration. Fourteen sulfate metabolites were quantified using mixed-mode solid-phase extraction and analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Urine samples after a single IM injection (100 mg) of T cypionate to six Caucasian and six Asian healthy male volunteers were analyzed. Principal component analysis (PCA) was used to characterize the sample cohort and to obtain the most useful markers for discrimination between pre- and post-administration samples. For Caucasian volunteers, a separation between pre- and post-administration samples was observed in PCA, whereas for Asian volunteers no separation was obtained. Seventeen ratios between sulfate metabolites were selected and further considered. Detection times (DTs) of each marker were evaluated using individual thresholds for each volunteer. The best results were obtained using ratios involving T and epitestosterone (E) sulfates in the denominator. The best marker was the ratio androsterone sulfate/testosterone sulfate (A-S/T-S) which prolonged the DT 1.2-2.1 times in respect to those obtained using T/E ratio in all Caucasian volunteers and 1.3-1.5 times in two Asian volunteers. Other ratios between A-S or etiocholanolone sulfate and E-S, and sulfates of etiocholanolone, dehydroandrosterone or epiandrosterone, and T-S were also found adequate. These ratios improve the DT after IM T administration and their incorporation to complement the current steroid profile is recommended.
Publication
Journal: Drug Testing and Analysis
November/21/2017
Abstract
In the fight against doping, the introduction of alternative markers to the steroid profile can be considered as an effective approach to improve the screening capabilities for the detection of testosterone (T) misuse. The aim of this study was to evaluate the potential of several T metabolites (cysteinyl conjugated and glucuronoconjugated resistant to enzymatic hydrolysis) to detect both the transdermal and the intramuscular administration of T. In Part I of the study, we studied the potential of these metabolites for the detection of T transdermal administration. Results revealed that resistant glucuronides can be a suitable complement to the current steroid profile. In this, Part II, dedicated to the intramuscular administration, we studied the potential of cysteinyl conjugated, resistant glucuronoconjugated and 1-cyclopentenoylglycine (1-CPG) for the detection of a single intramuscular injection of T cypionate. Possible differences in the excretion profile of all markers were explored between individuals with low basal (n=6) and medium basal (n=6) values of the testosterone/epitestosterone ratio (T/E). The results showed that all tested markers presented low intra-individual stability in basal conditions. Despite this, all glucuronoconjugated markers and 1-CPG, but not the cysteinyl conjugated markers, provided detection windows that were similar or longer than those obtained by markers currently included in the steroid profile. Based on the results obtained from the 2 parts of this study and from previously reported data, the potential applicability and the limitations of including these markers in the steroid profile are discussed.
Publication
Journal: Rapid Communications in Mass Spectrometry
February/3/2014
Abstract
BACKGROUND
The analysis of urinary metabolites of testosterone-related steroids through the measurement of their carbon isotopic signature (δ(13) C) by gas chromatography/combustion/mass spectrometry (GC/C/IRMS) is a confirmation method employed in doping control analyses. Stringent analytical conditions are essential to an accurate and precise analysis as well as the proper selection of the metabolites, which forms the basis of the refined method presented in this paper.
METHODS
In a simplified approach, following enzymatic hydrolysis and extraction from a relatively low volume of urine sample, a one-step high-performance liquid chromatography (HPLC) purification was developed for seven diagnostic urinary metabolites (TS) including testosterone itself, dehydroepiandrosterone, 5α- and 5β-androstanediol, epitestosterone, androsterone, etiocholanolone and two endogenous reference compounds (ERC), 5β-pregnanediol and 5α-androst-16-en-3β-ol. These steroids were pooled in three fractions and analyzed as such. With regards to the GC/C/IRMS analysis, a multi-level isotopic calibration using the 'identical treatment' principle was created.
RESULTS
The proposed isotopic calibration yielded results for purified reference steroids with a precision ≤0.15 and accuracy of ≤0.30 ‰ (between-assay, n = 26). Compared to other common endogenous reference compounds, those selected in this study had δ(13) C values close to the target metabolites which, along with the proposed isotopic calibration, produced narrow reference intervals within ± 3‰ for most diagnostic TS-ERC pairs, in compliance with the requirements of the World Anti-Doping Agency.
CONCLUSIONS
These carefully controlled analytical conditions are compatible with routine operations, affording accurate and precise results for the more diagnostically relevant metabolites such as testosterone itself and the 5α- and 5β-androstanediols. The values of the TS-ERC pairs measured in reference populations are described and the results from the routine testing of several hundreds of athletes' samples are discussed. Robust, this technique permitted the detection of adverse findings that would have been missed had these low level metabolites not been analyzed.
Publication
Journal: Journal of Chromatographic Science
July/31/2003
Abstract
An isocratic high-performance liquid chromatographic method for the determination of testosterone (T) and epitestosterone (ET) in human urine using liquid-liquid or solid-phase extraction (SPE) is developed and validated. The optimum separation is achieved using a Hypersil C(18) column, water-acetonitrile (57:43, v/v) as the mobile phase and UV-absorbance detection at 245 nm. The recoveries obtained for T and ET in liquid-liquid and SPE demonstrate that these procedures are interchangeable. Quantitation limits for T and ET are 8.6 and 5.4 ng/mL using solvent extraction and 7.3 and 5.7 ng/mL using SPE, respectively. The proposed method is used to evaluate the urinary T, ET, and the T/ET ratio for a healthy male population using liquid-liquid extraction, and the T and ET excretion profile for nine healthy men using SPE.
Publication
Journal: The Scientific World Journal
July/12/2012
Abstract
The validated micellar electrokinetic chromatography (MEKC) was proposed for the determination of five steroid hormones in human urine samples. That technique allowed for the separation and quantification of cortisol, cortisone, corticosterone, testosterone, and epitestosterone and was sensitive enough to detect low concentrations of these searched steroids in urine samples at the range of 2-300 ng/mL. The proposed MEKC technique with solid-phase extraction (SPE) procedure was simple, rapid, and has been successfully applied as a routine procedure to analyze steroids in human urine samples. The MEKC method offered a potential in clinical routine practice because of the short analysis time (8 min), low costs, and simultaneous analysis of five endogenous hormones. Due to its simplicity, speed, accuracy, and high recovery, the proposed method could offer a tool to determine steroid hormones as potential biomarkers in biomedical investigations, what was additionally revealed with healthy volunteers.
Publication
Journal: Bioanalysis
April/7/2011
Abstract
BACKGROUND
A thin sheet of polydimethylsilosane membrane was used as an extraction phase for solid-phase microextraction. Compared with fiber or rod solid-phase microextraction geometries, the thin film exhibited much higher extraction capacity without sacrificing extraction time due to its higher area-to-volume ratio. The analytical method involved direct extraction of unconjugated testosterone (T) and epitestosterone (ET) followed by separation on a C18 column and detection by selected reaction monitoring in positive ionization mode.
RESULTS
The limit of detection was 1 ng/l for both T and ET. After method validation, free (unconjugated) T and ET were extracted and quantified in real samples. Since T and ET are extensively metabolized, the proposed method was also applied to extract the steroids after enzymatic deconjugation of urinary-excreted steroid glucuronides.
CONCLUSIONS
The proposed method allows quantification of both conjugated and unconjugated steroids, and revealed that there was a change in the ratio of T to ET after enzymatic deconjugation, indicating different rates of metabolism.
Publication
Journal: Biomedical mass spectrometry
May/22/1979
Abstract
Quantitative analyses of testosterone, as the methyl oxime t-butyldimethylsilyl ether, are performed by gas chromatography mass spectrometry with selected monitoring of the metastable peak corresponding to the fragmentation [M]+. leads to [M-C4H9]+ in the field free region preceding the electric sector of a double focusing mass spectrometer. A detection limit of c. 30 pg is observed during analyses of the standard compound. The method is applied to the quantitative determination of testosterone in extracts of prostatic tissue from the golden hamster, using epitestosterone as the internal standard. The analytical specificity is similar to that achieved during gas chromatography high resolution mass spectrometry with selected ion detection of [M]+. ions; gas chromatography low resolution mass spectrometry is of inadequate specificity.
Publication
Journal: Biological mass spectrometry
September/23/1993
Abstract
Testosterone doping in sport is detected by measurement of an increased testosterone/epitestosterone (T/E) ratio in urine. The critical limit is 6. The present study concerns calibration curves for the T/E ratio measured by gas chromatography/mass spectrometry (electron impact) according to the guidelines of the International Olympic Committee. Testosterone (T) and epitestosterone (E) are measured as trimethylsilyl (TMS)-enol-TMS ethers in selected ion monitoring mode using m/z 432 with methyltestosterone (MT) (m/z 446) as internal standard. Calibration curves corresponding to T/E = 1, 6 and 12 prepared directly, i.e. without extraction of T and E, were non-linear. The non-linearity was caused by an increase of the relative molar response of T with respect to the internal standard MT with increasing concentration level. A mean increase of 82% was observed from T/E = 1 to T/E = 12 (E fixed). Adding T/E corresponding to 1/1, 6/1 and 12/1 to urine without endogeneous hormone content resulted in an almost linear calibration curve along the diagonal, with only a slight increase of the relative molar response of testosterone (16% from T/E = 1 to 12). Apparently, the biological matrix stabilizes the relative molar response over a wide concentration range. At a molar ratio of about 1/1 for T/MT, the relative molar response for direct measurement of T is identical to that observed in the presence of urine matrix, which is explained on the basis of a simple mathematical model. The practical conclusion of this study is that, contrary to the present-day practice, calibration curves for the T/E ratio should be based on T/E added to blank urine taken through the extraction procedure. Otherwise, the T/E ratio of urine sample is systematically easily underestimated by 30% or more.
Authors
Publication
Journal: Steroids
August/31/2018
Abstract
Conjugates of 17α-substituted testosterone (1 and 2) and 17β-substituted epitestosterone (3 and 4) with pyropheophorbide a were synthesized. The scheme consisted of synthesis of 17α-hydroxy-3-oxopregn-4-en-21-oic and 17β-hydroxy-3-oxopregn-4-en-21-oic acids, and their coupling with pyropheophorbide a by means of either ethylene diamine, or 1,5-diamino pentane linkers. Mutual influence of steroidal and macrocyclic fragments in conjugates molecules was dependent on configuration of C17 and length of linker, that was established by analysis of 1H NMR spectra and molecular models of conjugates. Studies of interaction of conjugates with prostate carcinoma cells revealed that their uptake and internalization were independent on the androgen receptor activity, but dependent on the structure of conjugates, decreasing in the following row: 3>> 4 ≥ 1>> 2. Conjugates significantly decreased the LNCaP and PC-3 cells growth at 96 h incubation. Epitestosterone derivatives 3 and 4 also showed superior anti-proliferative activity versus testosterone ones. Conformationally more rigid conjugates 1 and 3, comprising short linkers, were more active than those with long linkers; conjugate 3 was the most potent.
Related with
Publication
Journal: Journal of Endocrinology
August/9/1981
Abstract
The concentration of total unconjugated oestrogens in the peripheral plasma of cows increased from 2.00 +/- 0.20 (S.E.M.) ng/ml 7 days before to 3.87 +/- 0.50 ng/ml 1 day before parturition and declined to values below 0.30 ng/ml on day 2 post partum. The concentrations of androstenedione, epitestosterone and testosterone remained approximately constant at 0.90 +/- 0.10, 0.92 +/- 0.08 and 0.40 +/- 0.20 ng/ml respectively during the last week of pregnancy. After parturition the concentration of the three androgens declined rapidly. Similar to data obtained in goats we did not find a marked increase in androgen levels in the peripheral blood of cows before parturition.
Publication
Journal: Clinical Chemistry
August/26/1981
Abstract
Highly specific methods are described for determining testosterone in plasma or serum from men. Extract fractions obtained by selective isolation procedures are converted to tert-butyldimethylsilyl (TBDMS) oximes/TBDMS ethers or methyl oximes/TBDMS ethers and analyzed by gas chromatography/mass spectrometry in the high-resolution selected-ion monitoring or metastable peak-monitoring modes. [2H3]Testosterone and unlabeled 17-epitestosterone are used as the respective internal standards. When we applied the two procedures to analysis of samples of pooled plasma and serum used for external quality assessment of routine assays, the results agreed well. Interlaboratory values for mean concentrations obtained by routine immunoassays (y) consistently exceeded values obtained by our technique (x), although the values closely correlated (r = 0.997; y = 1.008x + 0.564 nmol/L).
Publication
Journal: Journal of Agricultural and Food Chemistry
September/21/2020
Abstract
Serum analysis has gained great attention in regulatory analysis of food producing animals, especially for anabolic steroids. The possibility of confirming the parent drugs with minimum metabolization enables the detection of intact steroid esters, whose identification represents unequivocal proof of drug administration. This work involved the development and validation of a quantitative LC-MS/MS method to determine 30 steroids and steroid esters in bovine serum. Sensitivity was improved using a microwave-assisted chemical derivatization with methoxyamine hydrochloride. The validation was successfully conducted in accordance with the Decision 657/2002/EC guidelines. An in vivo experiment was performed on twelve crossbred steers in which two commercial formulations containing boldenone undecylenate and testosterone propionate were administrated via intramuscular injections. The samples were collected over a period of 120 days, in which both intact esters were identified within 11 days post-administration. 17β-boldenone was observed after 92 days for 2 steers, and 56 for the other animals. The applicability of a cut off level to the ratio between 17β-testosterone and epitestosterone was evaluated in an attempt to differentiate testosterone abuse from endogenous production. It could be observed that a calculated ratio above this level is a strong evidence of drug administration, although a high false-negative rate was obtained.
Publication
Journal: Drug Testing and Analysis
November/20/2018
Abstract
The detection of testosterone (T) misuse is performed using the steroid profile that includes concentrations of T and related metabolites excreted free and glucuronoconjugated, and the ratios between them. In this work, the usefulness of 14 endogenous steroid sulfates to improve the detection capabilities of oral T administration has been evaluated. Quantitation of the sulfate metabolites was performed using solid-phase extraction and analysis by liquid chromatography-tandem mass spectrometry. Urine samples were collected up to 144 hours after a single oral dose of T undecanoate (120 mg) to five Caucasian male volunteers. Detection times (DTs) of each marker were estimated using reference limits based on a population study and also monitoring the individual threshold for each volunteer. High inter-individual variability was observed for sulfate metabolites and, therefore, better DTs were obtained using individual thresholds. Using individual threshold limits, epiandrosterone sulfate (epiA-S) improved the DT with respect to testosterone/epitestosterone (T/E) ratio in all volunteers. Androsterone, etiocholanolone, and two androstanediol sulfates also improved DTs for some volunteers. Principal component analysis was used to characterize the sample cohort, obtaining 13 ratios useful for discrimination. These ratios as well as the ratio epiA-S/dehydroepiandrosterone sulfate were further examined. The most promising results were obtained using ratios between sulfates of epiA, androsterone, or androstanediol 1 and E, and also sulfates of epiA or androstanediol 1, and dehydroandrosterone. These selected ratios prolonged the DT of oral T administration up to 144 hours, which corresponded to a significantly higher retrospectivity compared to those obtained using concentrations or the conventional T/E ratio.
Related with
load more...