A new method for hydrolyzing sulfate and glucuronyl conjugates of steroids

The evolution of methods for urinary steroid metabolomics in clinical investigations particularly in childhood

The metabolites of cortisol, and the intermediates in the pathways from cholesterol to cortisol and the adrenal sex steroids can be analysed in a single separation of steroids by gas chromatography (GC) coupled to MS to give a urinary steroid profile (USP). Steroids individually and in profile are now commonly measured in plasma by liquid chromatography (LC) coupled with MS/MS. The steroid conjugates in urine can be determined after hydrolysis and derivative formation and for the first time without hydrolysis using GC-MS, GC-MS/MS and liquid chromatography with mass spectrometry (LC-MS/MS). The evolution of the technology, practicalities and clinical applications are examined in this review. The patterns and quantities of steroids changes through childhood. Information can be obtained on production rates, from which children with steroid excess and deficiency states can be recognised when presenting with obesity, adrenarche, adrenal suppression, hypertension, adrenal tumours, intersex condition and early puberty, as examples. Genetic defects in steroid production and action can be detected by abnormalities from the GC-MS of steroids in urine. New mechanisms of steroid synthesis and metabolism have been recognised through steroid profiling. GC with tandem mass spectrometry (GC-MS/MS) has been used for the tentative identification of unknown steroids in urine from newborn infants with congenital adrenal hyperplasia. Suggestions are made as to areas for future research and for future applications of steroid profiling. As routine hospital laboratories become more familiar with the problems of chromatographic and MS analysis they can consider steroid profiling in their test repertoire although with LC-MS/MS of urinary steroids this is unlikely to become a routine test because of the availability, cost and purity of the internal standards and the complexity of data interpretation. Steroid profiling with quantitative analysis by mass spectrometry (MS) after chromatography now provides the most versatile of tests of adrenal function in childhood.

Ultra-high sensitivity analysis of estrogens for special populations in serum and plasma by liquid chromatography-mass spectrometry: Assay considerations and suggested practices

Estrogen measurements play an important role in the clinical evaluation of many endocrine disorders as well as in research on the role of hormones in human biology and disease. It remains an analytical challenge to quantify estrogens and their metabolites in specimens from special populations including older men, children, postmenopausal women and women receiving aromatase inhibitors. Historically, immunoassays have been used for measuring estrogens and their metabolites in biological samples for risk assessment. However, the lack of specificity and accuracy of immunoassay-based methods has caused significant problems when interpreting data generated from epidemiological studies and across different laboratories. Stable isotope dilution (SID) methodology coupled with liquid chromatography-selected reaction monitoring-mass spectrometry (LC-SRM/MS) is now accepted as the 'gold-standard' to quantify estrogens and their metabolites in serum and plasma due to improved specificity, high accuracy, and the ability to monitor multiple estrogens when compared with immunoassays. Ultra-high sensitivity can be obtained with pre-ionized derivatives when using triple quadruple mass spectrometers in the selected reaction monitoring (SRM) mode coupled with nanoflow LC. In this review, we have examined the special issues related to utilizing ultra-high sensitivity SID LC-SRM/MS-based methodology to accurately quantify estrogens and their metabolites in the serum and plasma from populations with low estrogen levels. The major issues that are discussed include: sample preparation for both unconjugated and conjugated estrogens, derivatization, chromatographic separation, matrix effects, and assay validation.

In vitro metabolism studies of desoxy-methyltestosterone (DMT) and its five analogues, and in vivo metabolism of desoxy-vinyltestosterone (DVT) in horses

The positive findings of norbolethone in 2002 and tetrahydrogestrinone in 2003 in human athlete samples confirmed that designer steroids were indeed being abused in human sports. In 2005, an addition to the family of designer steroids called 'Madol' [also known as desoxy-methyltestosterone (DMT)] was seized by government officials at the US-Canadian border. Two years later, a positive finding of DMT was reported in a mixed martial arts athlete's sample. It is not uncommon that doping agents used in human sports would likewise be abused in equine sports. Designer steroids would, therefore, pose a similar threat to the horseracing and equestrian communities. This paper describes the in vitro metabolism studies of DMT and five of its structural analogues with different substituents at the 17α position (RH, ethyl, vinyl, ethynyl and ² H₃ -methyl). In addition, the in vivo metabolism of desoxy-vinyltestosterone (DVT) in horses will be presented. The in vitro studies revealed that the metabolic pathways of DMT and its analogues occurred predominantly in the A-ring by way of a combination of enone formation, hydroxylation and reduction. Additional biotransformation involving hydroxylation of the 17α-alkyl group was also observed for DMT and some of its analogues. The oral administration experiment revealed that DVT was extensively metabolised and the parent drug was not detected in urine. Two in vivo metabolites, derived respectively from (1) hydroxylation of the A-ring and (2) di-hydroxylation together with A-ring double-bond reduction, could be detected in urine up to a maximum of 46 h after administration. Another in vivo metabolite, derived from hydroxylation of the A-ring with additional double-bond reduction and di-hydroxylation of the 17α-vinyl group, could be detected in urine up to a maximum of 70 h post-administration. All in vivo metabolites were excreted mainly as glucuronides and were also detected in the in vitro studies. Copyright © 2015 John Wiley & Sons, Ltd.

Metabolic study of androsta-1,4,6-triene-3,17-dione in horses using liquid chromatography/high resolution mass spectrometry

Androsta-1,4,6-triene-3,17-dione (ATD) is an irreversible steroidal aromatase inhibitor and is marketed as a supplement. It has been reported to effectively reduce estrogen biosynthesis and significantly increase the levels of endogenous steroids such as dihydrotestosterone and testosterone in human. ATD abuses have been reported in human sports. Its metabolism in human has been studied, and the in vitro metabolic study of ATD in horses has been reported, however, little is known about its biotransformation and elimination in horses. This paper describes the in vitro and in vivo metabolism studies of ATD in horses, with an objective of identifying the target metabolites with the longest detection time for controlling ATD abuse. In vitro metabolism studies of ATD were performed using homogenized horse liver. ATD was found to be extensively metabolized, and its metabolites could not be easily characterized by gas chromatography/mass spectrometry (GC/MS) due to insufficient sensitivity. Liquid chromatography/high resolution mass spectrometry (LC/HRMS) was therefore employed for the identification of in vitro metabolites. The major biotransformations observed were combinations of reduction of the olefin groups and/or the keto group at either C3 or C17 position. In addition, mono-hydroxylation in the D-ring was observed along with reduction of the olefin groups and/or the keto group at C17 position. Fourteen in vitro metabolites, including two epimers of androsta-1,4,6-trien-17-ol-3-one (M1a, M1b), androsta-4,6-diene-3,17-dione (M2), boldione (M3), androsta-4,6-diene-17β-ol-3-one (M4), androsta-4,6-diene-3-ol-17-one (M5), boldenone and epi-boldenone (M6a, M6b), four stereoisomers of hydroxylated androsta-1,4,6-trien-17-ol-3-one (M7a to M7d), and two epimers of androsta-1,4-diene-16α,17-diol (M8a, M8b), were identified. The identities of all metabolites, except M1a, M5, M7a to M7d, were confirmed by matching with authentic reference standards using LC/HRMS. For the in vivo metabolism studies, two thoroughbred geldings were each administered with 800 mg of ATD by stomach tubing. ATD, and twelve out of the fourteen in vitro metabolites, including M1a, M1b, M2, M4, M5, M6, M7a to M7d, M8a and M8b, were detected in post-administration urine. Two additional urinary metabolites, namely stereoisomers of hydroxylated androsta-4,6-dien-17-ol-3-one (M9a, M9b), were tentatively identified by mass spectral interpretation. Elevated level of testosterone was also observed. In post-administration blood samples, only the parent drug, M1b and M2 were identified. This study showed that the detection of ATD administration would be best achieved by either monitoring the metabolites M1b (androsta-1,4,6-trien-17β-ol-3-one) or M4 (both excreted as sulfate conjugates) in urine, which could be detected for up to a maximum of 77 h post-administration. The analyte of choice for plasma is M1b, which could be detected for up to 28 h post administration.

Analysis of estrogens and androgens in postmenopausal serum and plasma by liquid chromatography-mass spectrometry

Liquid chromatography-selected reaction monitoring/mass spectrometry-based methodology has evolved to the point where accurate analyses of trace levels of estrogens and androgens in postmenopausal serum and plasma can be accomplished with high precision and accuracy. A suite of derivatization procedures has been developed, which together with modern mass spectrometry instrumentation provide investigators with robust and sensitive methodology. Pre-ionized derivatives are proving to be useful as they are not subject to suppression of the electrospray signal. Postmenopausal women with elevated plasma or serum estrogens are thought to be at increased risk for breast and endometrial cancer. Therefore, significant advances in risk assessment should be possible now that reliable methodology is available. It is also possible to conduct analyses of multiple estrogens in plasma or serum. Laboratories that are currently employing liquid chromatography/mass spectrometry methodology can now readily implement this strategy. This will help conserve important plasma and serum samples available in Biobanks, as it will be possible to conduct high sensitivity analyses using low initial sample volumes. Reported levels of both conjugated and non-conjugated estrogen metabolites are close to the limits of sensitivity of many assays to date, urging caution in the interpretation of these low values. The analysis of serum androgen precursors in postmenopausal women has not been conducted routinely in the past using liquid chromatography/mass spectrometry methodology. Integration of serum androgen levels into the panel of metabolites analyzed could provide additional information for assessing cancer risk and should be included in the future.

Bringing GC-MS profiling of steroids into clinical applications

Abnormalities of steroid biosynthesis and excretion are responsible for the development and prevention of endocrine disorders, such as metabolic syndromes, cancers, and neurodegenerative diseases. Due to their biochemical roles in endocrine system, qualitative and quantitative analysis of steroid hormones in various biological specimens is needed to elucidate their altered expression. Mass spectrometry (MS)-based steroid profiling can reveal the states of metabolites in biological systems and provide comprehensive insights by allowing comparisons between metabolites present in cells, tissues, or organisms. In addition, the activities of many enzymes related to steroid metabolism often lead to hormonal imbalances that have serious consequences, and which are responsible for the progress of hormone-dependent diseases. In contrast to immunoaffinity-based enzyme assays, MS-based methods are more reproducible in quantification. In particular, high-resolution gas chromatographic (GC) separation of steroids with similar chemical structures can be achieved to provide rapid and reproducible results with excellent purification. GC-MS profiling therefore has been widely used for steroid analysis, and offers the basis for techniques that can be applied to large-scale clinical studies. Recent advances in analytical technologies combined with inter-disciplinary strategies, such as physiology and bioinformatics, will help in understanding the biochemical roles of steroid hormones. Therefore, comprehensive analytical protocols in steroid analysis for different research purposes may contribute to the elucidation of complex metabolic processes relevant to steroid function in many endocrine disorders, and in the identification of diagnostic biomarkers.

The metabolism of anabolic-androgenic steroids in the greyhound

BACKGROUND

Effective control of the use of anabolic-androgenic steroids (AASs) in animal sports is essential in order to ensure both animal welfare and integrity. In order to better police their use in Australian and New Zealand greyhound racing, thorough metabolic studies have been carried out on a range of registered human and veterinary AASs available in the region.

RESULTS

Canine metabolic data are presented for the AASs boldenone, danazol, ethylestrenol, mesterolone, methandriol, nandrolone and norethandrolone. The principal Phase I metabolic processes observed were the reduction of A-ring unsaturations and/or 3-ketones with either 3α,5β- or 3β,5α-stereochemistry, the oxidation of secondary 17β-hydroxyl groups and 16α-hydroxylation. The Phase II β-glucuronylation of sterol metabolites was extensive.

CONCLUSION

The presented data have enabled the effective analysis of AASs and their metabolites in competition greyhound urine samples.

Metabolism of stanozolol: chemical synthesis and identification of a major canine urinary metabolite by liquid chromatography-electrospray ionisation ion trap mass spectrometry

The canine phase I and phase II metabolism of the synthetic anabolic-androgenic steroid stanozolol was investigated following intramuscular injection into a male greyhound. The major phase I biotransformation was hydroxylation to give 6alpha-hydroxystanozolol which was excreted as a glucuronide conjugate and was identified by comparison with synthetically derived reference materials. An analytical procedure was developed for the detection of this stanozolol metabolite in canine urine using solid phase extraction, enzyme hydrolysis of glucuronide conjugates and analysis by positive ion electrospray ionisation ion trap LC-MS.

Modern techniques for the determination of anabolic–androgenic steroid doping in the horse

Control of the use of performance-affecting substances in the horse is critical to the integrity of a wide range of equine sports, with major implications for both animal welfare and revenue streams. One class of medications enjoying particular public notoriety is the anabolic–androgenic steroid group, as highlighted by the recent ‘Big Brown’ affair and Congressional inquiries into the use of steroids in professional sports, including horse racing, in the USA. This review examines the latest developments pertaining to the analytical detection of these substances in equine biological samples and the supporting regulatory environment. Consideration is given to the full variety of sample matrices available, together with modern sample preparative approaches and instrumental techniques. Issues concerning the regulation of endogenous steroids, including thresholds where applicable, are also discussed.

Fate of conjugated natural and synthetic steroid estrogens in crude sewage and activated sludge batch studies

Steroids are excreted from the human body in the conjugated form but are present in sewage influent and effluent as the free steroid, the major source of estrogenic activity observed in water courses. The fate of sulfate and glucuronide conjugated steroid estrogens was investigated in batch studies using activated sludge grown on synthetic sewage in a laboratory-scale Husmann simulation and crude sewage from the field. A clear distinction between the fate of sulfate and glucuronide conjugates was observed in both matrices, with sulfated conjugates proving more recalcitrant and glucuronide deconjugation preferential in crude sewage. For each conjugate, the free steroid was observed in the biotic samples. The degree of free steroid formation was dependent on the conjugate moiety, favoring the glucuronide. Subsequent degradation of the free steroid (and sorption to the activated sludge solid phase) was evaluated. Deconjugation followed the first order reaction rate with rate constants for 17alpha-ethinylestradiol 3-glucuronide, estriol l6alpha-glucuronide, and estrone 3-glucuronide determined as 0.32, 0.24, and 0.35 h respectively. The activated sludge solid retention time over the range of 3-9 days had 74 to 94% of sulfate conjugates remaining after 8 h. In contrast, a correlation between increasing temperature and decreasing 17alpha-ethinylestradiol 3-glucuronide concentrations in the activated sludge observed no conjugate present in the AS following 8 h at 22 degrees C Based on these batch studies and literature excretion profiles, a hypothesis is presented on which steroids and what form (glucuronide, sulfate, or free) will likely enter the sewage treatment plant.

Unusual observations during steroid analysis

In September 2005, our laboratory detected the presence of 4-androstene-3,17-dione and androsterone in a standard steroid screen of a post-race gelding urine sample received from an overseas authority. All other urine samples from the same batch tested negative. Subsequent gas chromatography/mass spectrometry (GC/MS) confirmatory analyses, however, repeatedly failed to detect any amount of 4-androstene-3,17-dione and androsterone in the suspicious sample. On the other hand, identical results were obtained when the initial GC/MS screening method was repeated on the suspicious sample as well as on the other samples of the same batch, showing the presence of 4-androstene-3,17-dione and androsterone only in the suspicious sample. These unusual and contradictory findings between the screening and confirmatory procedures were investigated, leading to the unequivocal conclusion that the 4-androstene-3,17-dione and androsterone observed during screening were artefacts from the internal standards, [16,16,17-d3]-testosterone and [16,16,17-d3]-5alpha-androstane-3alpha,17beta-diol. The two deuterated internal standards were thought to have undergone first an enzymatic oxidation of the 17beta-hydroxyl group to a 17-keto function by the enzyme 17beta-hydroxysteroid dehydrogenase; complete deuterium-hydrogen exchange at C16 during the methanolysis deconjugation step would then produce the two artefacts. The findings from this study highlight the potential problem of using internal standards in qualitative confirmatory analyses, which may lead to undesirable false positive results.

Induction of CYP1A1 and CYP1B1 by benzo(k)fluoranthene and benzo(a)pyrene in T-47D human breast cancer cells: roles of PAH interactions and PAH metabolites

The interactions of polycyclic aromatic hydrocarbons (PAH) and cytochromes P450 (CYP) are complex; PAHs are enzyme inducers, substrates, and inhibitors. In T-47D breast cancer cells, exposure to 0.1 to 1 microM benzo(k)fluoranthene (BKF) induced CYP1A1/1B1-catalyzed 17beta-estradiol (E(2)) metabolism, whereas BKF levels greater than 1 muM inhibited E(2) metabolism. Time course studies showed that induction of CYP1-catalyzed E(2) metabolism persisted after the disappearance of BKF or co-exposed benzo(a)pyrene, suggesting that BKF metabolites retaining Ah receptor agonist activity were responsible for prolonged CYP1 induction. BKF metabolites were shown, through the use of ethoxyresorufin O-deethylase and CYP1A1-promoter-luciferase reporter assays to induce CYP1A1/1B1 in T-47D cells. Metabolites formed by oxidation at the C-2/C-3 region of BKF had potencies for CYP1 induction exceeding those of BKF, whereas C-8/C-9 oxidative metabolites were somewhat less potent than BKF. The activities of expressed human CYP1A1 and 1B1 with BKF as substrate were investigated by use of HPLC with fluorescence detection, and by GC/MS. The results showed that both enzymes efficiently catalyzed the formation of 3-, 8-, and 9-OHBKF from BKF. These studies indicate that the inductive effects of PAH metabolites as potent CYP1 inducers are likely to be additional important factors in PAH-CYP interactions that affect metabolism and bioactivation of other PAHs, ultimately modulating PAH toxicity and carcinogenicity.

Metabolic studies of mesterolone in horses

Mesterolone (1alpha-methyl-5alpha-androstan-17beta-ol-3-one) is a synthetic anabolic androgenic steroid (AAS) with reported abuses in human sports. As for other AAS, mesterolone is also a potential doping agent in equine sports. Metabolic studies on mesterolone have been reported for humans, whereas little is known about its metabolic fate in horses. This paper describes the studies of both the in vitro and in vivo metabolism of mesterolone in racehorses with an objective to identify the most appropriate target metabolites for detecting mesterolone administration. In vitro biotransformation studies of mesterolone were performed by incubating the steroid with horse liver microsomes. Metabolites in the incubation mixture were isolated by liquid-liquid extraction and analysed by gas chromatography-mass spectrometry (GC-MS) after acylation or silylation. Five metabolites (M1-M5) were detected. They were 1alpha-methyl-5alpha-androstan-3alpha-ol-17-one (M1), 1alpha-methyl-5alpha-androstan-3beta-ol-17-one (M2), 1alpha-methyl-5alpha-androstane-3alpha,17beta-diol (M3), 1alpha-methyl-5alpha-androstane-3beta,17beta-diol (M4), and 1alpha-methyl-5alpha-androstane-3,17-dione (M5). Of these in vitro metabolites, M1, M3, M4 and M5 were confirmed using authentic reference standards. M2 was tentatively identified by mass spectral comparison to M1. For the in vivo metabolic studies, Proviron (20 tablets x 25 mg of mesterolone) was administered orally to two thoroughbred geldings. Pre- and post-administration urine samples were collected for analysis. Free and conjugated metabolites were isolated using solid-phase extraction and analysed by GC-MS as described for the in vitro studies. The results revealed that mesterolone was extensively metabolised and the parent drug was not detected in urine. Three metabolites detected in the in vitro studies, namely M1, M2 and M4, were also detected in post-administration urine samples. In addition, two stereoisomers each of 1alpha-methyl-5alpha-androstane-3,17alpha-diol (M6 and M7) and 1alpha-methyl-5alpha-androstane-3,16-diol-17-one (M8 and M9), and an 18-hydroxylated metabolite 1alpha-methyl-5alpha-androstane-3,18-diol-17-one (M10) were also detected. The metabolic pathway for mesterolone is postulated. These studies have shown that metabolites M8, M9 and M10 could be used as potential screening targets for controlling the misuse of mesterolone in horses.

Metabolic studies of turinabol in horses

Turinabol (4-chloro-17alpha-methyl-17beta-hydroxy-1,4-androstadien-3-one) is a synthetic oral anabolic androgenic steroid. As in the case of other anabolic steroids, it is a prohibited substance in equine sports. The metabolism of turinabol in human has been reported previously; however, little is known about its metabolic fate in horses. This paper describes the studies of both the in vitro and in vivo metabolism of turinabol in racehorses with an objective to identify the most appropriate target metabolites for detecting turinabol administration. For the in vitro studies, turinabol was incubated with fresh horse liver microsomes. Metabolites in the incubation mixture were isolated by liquid-liquid extraction and analysed by gas chromatography-mass spectrometry (GC-MS) after trimethylsilylation. The results showed that the major biotransformation of turinabol was hydroxylation at the C6, C16 and C20 sites to give metabolites 6beta-hydroxyturinabol (M1), 20-hydroxyturinabol (M2), two stereoisomers of 6beta,16-dihydroxyturinabol (M3a, M3b) and 6beta,20-dihydroxyturinabol (M4). The metabolite 6beta-hydroxyturinabol was confirmed using an authentic reference standard. The structures of all other turinabol metabolites were tentatively identified by mass spectral interpretation. For the in vivo studies, two horses were administered orally with turinabol. Pre- and post-administration urine samples were collected for analysis. Free and conjugated metabolites were isolated using solid-phase extraction and analysed by GC-MS as described for the in vitro studies. The results revealed that turinabol was extensively metabolised and the parent drug was not detected in urine. Two metabolites detected in the in vitro studies, namely 20-hydroxyturinabol and 6beta,20-dihydroxyturinabol, these were also detected in post-administration urine samples. In addition, 17-epi-turinabol (M5) and six other metabolites (M6a-M6c and M7a-M7c), derived from D-ring hydroxylation and A-ring reduction, were also detected. Except for 17-epi-turinabol, none of these metabolites has ever been reported in any species. All in vivo metabolites were detected within 48 h after administration.

Detection and quantification of glucuro- and sulfoconjugated metabolites in human urine following oral administration of xenobiotic 19-norsteroids

Recently, the endogenous origin of nandrolone (19-nortestosterone) and other 19-norsteroids has been a focus of research in the field of drug testing in sport. In the present study, we investigated metabolites conjugated to a glucuronic acid and to a sulfuric acid in urine following administration of four xenobiotic 19-norsteroids. Adult male volunteers administered a single oral dose (10 mg) of each of four 19-norsteroids. Urinary samples collected from 0 to 120 h were subjected to methanolysis and beta-glucuronidase hydrolysis and were derivatized by N-methyl-N-trimethylsilyltrifluoroacetamide (MSTFA) before gas chromatography-mass spectrometry analysis. We confirmed that 19-norandrosterone (19-NA) and 19-noretiocholanolone (19-NE) were present in both glucuronide (g) and sulfate (s) conjugates and 19-norepiandrosterone (19-NEA) was excreted exclusively as a sulfate fraction in urine of all 19-norsteroids tested. The overall levels of the three metabolites can be ranked as follows: 19-NA(g+s)>19-NE(g+s)>19-NEA(s). The concentration profiles of these three metabolites in urine peaked between 2 to 12h post-administration and declined thereafter until approximately 72-96 h. 19-NA was most prominent throughout the first 24 h post-administration, except for a case in which an inverse relationship was found after 6h post-administration of nandrolone. Furthermore, we found that sulfate conjugates were present in both 19-NA and 19-NE metabolites in urine of all 19-norsteroids tested. The averaged total amounts of metabolites (i.e. 19-NA(s+g)+19-NE(s+g)+19-NEA(s)) excreted in urine were 38.6, 42.9, 48.3 and 21.6% for nandrolone, 19-nor-4-androsten-3,17-dione, 19-nor-4-androsten-3beta,17beta-diol and 19-nor-5-androstene-3beta,17beta-diol, respectively. Results from the excretion studies demonstrate significance of sulfate-conjugated metabolites on interpretation of misuse of the 19-norsteroids.

Alteration of steroid hormone profile in juvenile turbot (Psetta maxima) as a consequence of short-term exposure to 17alpha-ethynylestradiol

The synthetic estrogen 17alpha-ethynylestradiol (EE2) is among the most potent xenoestrogens found in treated sewage. Adverse effects have been reported in fish exposed to this chemical, such as vitellogenin induction or alteration of gonad structure. In this study, the effects of EE2 on sex steroid profile in juvenile turbot (Psetta maxima) were investigated in a 15-day in vivo experiment. An analytical method was developed for the simultaneous gas chromatography/mass spectrometry determination of 14 steroids in gonads, plasma and bile. The impact of EE2 on the endocrine status of juvenile turbot was sex-dependent, since males were much more sensitive than females. Even at very low concentration (3.5 ng l(-1)), EE2 depressed androgen production as well as plasma levels in males. Androstenedione and 11-ketotestosterone were highly affected by EE2-exposure, since their production was suppressed in EE2-treated males. Furthermore, testis estrogen production and conjugation increased as a consequence of EE2 exposure. Overall, the ratio of androgens to estrogens in EE2-exposed males dropped in testis and plasma and reached values observed in females. These results indicate that juvenile male turbots are susceptible to hormonal imbalance as a consequence of short-term exposure to environmentally relevant EE2 levels.

Determination of urinary steroid sulfate metabolites using ion paired extraction

The need for laboratories accredited by the World Anti-Doping Agency (WADA) to develop methods of analysis for steroids excreted primarily as their sulfate conjugates has faced significant analytical challenges. One of the issues relates to the extraction of these metabolites from urine in a relatively pure state. The use of (-)-N,N-dimethylephedrinium bromide as an ion pairing reagent was optimised to produce a method that is selective for the extraction of steroid sulfates prior to GC-MS or LC-MS analysis, with minimal contributions from the urine matrix. The recovery of androsterone from its sulfate conjugate was determined to be 67% with a relative quantitative uncertainty of +/-14% (k = 2).

Analysis of anabolic steroids in the horse: development of a generic ELISA for the screening of 17alpha-alkyl anabolic steroid metabolites

Due to the potential for misuse of a wide range of anabolic steroids in horse racing, a screening test to detect multiple compounds, via a common class of metabolites, would be a valuable forensic tool. An enzyme-linked immunosorbent assay (ELISA) has been developed to detect 17alpha-alkyl anabolic steroid metabolites in equine urine. 16beta-Hydroxymestanolone (16beta,17beta-dihydroxy-17alpha-methyl-5alpha-androstan-3-one) was synthesised in six steps from commercially available epiandrosterone (3beta-hydroxy-5alpha-androstan-17-one). Polyclonal antibodies were raised in sheep, employing mestanolone (17beta-hydroxy-17alpha-methyl-5alpha-androstan-3-one) or 16beta-hydroxymestanolone conjugated to human serum albumin, via a 3-carboxymethyloxime linker, as antigens. Antibody cross-reactivities were determined by assessing the ability of a library of 54 representative steroids to competitively bind the antibodies. Antibodies raised against 16beta-hydroxymestanolone showed excellent cross-reactivities for all of the 16beta,17beta-dihydroxy-17alpha-methyl steroids analysed and an ELISA has been developed to detect these steroid metabolites. Using this 16beta-hydroxymestanolone assay, urine samples from horses administered with stanozolol (17alpha-methyl-pyrazolo[4',3':2,3]-5alpha-androstan-17beta-ol), were analysed raw, following beta-glucuronidase hydrolysis, and following solid-phase extraction (SPE) procedures. The suppressed absorbances observed were consistent with detection of the metabolite 16beta-hydroxystanozolol. Positive screening results were confirmed by comparison with standard LCMS analyses. Antibodies raised against mestanolone were also used to develop an ELISA and this was used to detect metabolites retaining the parent D-ring structure following methandriol (17alpha-methylandrost-5-ene-3beta,17beta-diol) administration. The ELISA methods developed have application as primary screening tools for detection of new and known anabolic steroid metabolites.

Screening of anabolic steroids in horse urine by liquid chromatography–tandem mass spectrometry

Anabolic steroids have the capability of improving athletic performance and are banned substances in the Olympic games as well as in horseracing and equestrian competitions. The control of their abuse in racehorses is traditionally performed by detecting the presence of anabolic steroids and/or their metabolite(s) in urine samples using gas chromatography-mass spectrometry (GC-MS). However, this approach usually requires tedious sample processing and chemical derivatisation steps and could be very insensitive in detecting certain steroids. This paper describes a high performance liquid chromatography-tandem mass spectrometry (HPLC-MS-MS) method for the detection of anabolic steroids that are poorly covered by GC-MS. Enzyme-treated urine was processed by solid-phase extraction (SPE) using a Bond Elut Certify cartridge, followed by a base wash for further cleanup. Separation of the steroids was carried out on a reversed-phase DB-8 column using 0.1% acetic acid and methanol as the mobile phase in a gradient elution programme. The mass spectrometer for the detection of the steroids was operated in the positive electrospray ionisation (ESI) mode with multiple reaction monitoring (MRM). Urine samples fortified with 15 anabolic steroids (namely, androstadienone, 1-androstenedione, bolasterone, boldione, 4-estrenedione, gestrinone, methandrostenolone, methenolone, 17alpha-methyltestosterone, norbolethone, normethandrolone, oxandrolone, stenbolone, trenbolone and turinabol) at low ng/mL levels were consistently detected. No significant matrix interference was observed at the retention times of the targeted ion masses in blank urine samples. The method specificity, sensitivity, precision, recoveries, and the performance of the enzyme hydrolysis step were evaluated. The successful application of the method to analyse methenolone acetate administration urine samples demonstrated that the method could be effective in detecting anabolic steroids and their metabolites in horse urine.

In vivo biotransformation of 17 alpha-methyltestosterone in the horse revisited: identification of 17-hydroxymethyl metabolites in equine urine by capillary gas chromatography/mass spectrometry

The in vivo phase I biotransformation of 17 alpha-methyltestosterone in the horse leads to the formation of a complex mixture of regio- and stereoisomeric C(20)O(2), C(20)O(3) and C(20)O(4) metabolites, excreted in urine as glucuronide and sulphate phase II conjugates. The major pathways of in vivo metabolism are the reduction of the A-ring (di- and tetrahydro), epimerisation at C-17 and oxidations mainly at C-6 and C-16. Some phase I metabolites have been identified previously by positive ion electron ionisation capillary gas chromatography/mass spectrometry (GC/EI + MS) mainly from the characteristic fragmentation patterns of their methyloxime-trimethylsilyl ether (MO-TMS), enol-TMS or TMS ether derivatives. Following oral administration of 17 alpha-methyltestosterone to two castrated thoroughbred male horses, the glucuronic acid conjugates excreted in post-administration urine samples were selectively hydrolysed by E. coli beta-glucuronidase enzymes. Unconjugated metabolites and the steroid aglycones obtained after enzymatic deconjugation were isolated from urine by solid-phase extraction, derivatised as MO-TMS ethers and analysed by GC/EI + MS. In addition to some of the known metabolites previously identified from the characteristic mass spectral fragmentation patterns of 17 alpha-methyl steroids, some isobaric compounds exhibiting a diagnostic loss of 103 mass units from the molecular ions with subsequent losses of trimethylsilanol or methoxy groups and an absence of the classical D-ring fragment ion were detected. From an interpretation of their mass spectra, these compounds were identified as 17-hydroxymethyl metabolites, formed in vivo in the horse by oxidation of the 17-methyl moiety of 17 alpha-methyltestosterone. This study reports on the GC/EI + MS identification of these novel 17-hydroxymethyl C(20)O(3) and C(20)O(4) metabolites of 17 alpha-methyltestosterone excreted in thoroughbred horse urine.

Some new aspects of 17alpha-estradiol metabolism in man

17Alpha-estradiol (1,3,5(10)-estratriene-3,17alpha-diol) together with a tracer dose of the tritium-labeled compound was administered orally and sublingually to male volunteers. The serum concentrations of 17alpha-estradiol (free and liberated by enzymatic hydrolysis) were quantified by GC/MS, and the serum total radioactivity and urinary radioactivity excretion were determined. After oral administration, 17alpha-estradiol was rapidly and intensively conjugated; only tiny quantities of the free steroid (<1% of total) appeared in serum. Sublingual administration resulted in temporary (up to 3 h p.a.) higher serum levels of the free compound. The metabolite patterns obtained by TLC of extracts from serum and urine demonstrated that 17alpha-estradiol is the subject of a poor phase I metabolism in man. A great discrepancy was found in the serum concentrations of 17alpha-estradiol (free + conjugated) determined by GC/MS and the serum radioactivity expressed in 17alpha-estradiol equivalents. By TLC analysis of the steroid conjugates extracted from serum, various 17alpha-estradiol conjugate peaks were found. By enzymatic hydrolysis with beta-glucuronidase/aryl sulfatase from Helix pomatia they were only partially cleaved. Thus, the difference between the serum radioactivity and the 17alpha-estradiol levels determined by GC/MS had to be attributed to an incomplete conjugate hydrolysis. It has been shown with the synthesized 17alpha-estradiol sulfate conjugates that only the 3-sulfate is cleaved by enzymatic hydrolysis, whereas the 17-sulfate group resists enzymatic hydrolysis. The methanolysis procedure (acetyl chloride in MeOH) has proved to be an efficient method for cleaving both the 3-sulfate group and the 17-sulfate group. In contrast to the 17alpha-estradiol conjugates in serum, the urinary conjugates were intensively split by the enzyme preparation. From this, it has to be concluded that the serum conjugates were deconjugated and newly reconjugated before urinary excretion.

Metabolism of methandrostenolone in the horse: a gas chromatographic-mass spectrometric investigation of phase I and phase II metabolism

The phase I and phase II metabolism of the anabolic steroid methandrostenolone was investigated following oral administration to a standardbred gelding. In the phase I study, metabolites were isolated from the urine by solid-phase extraction, deconjugated by acid catalysed methanolysis and converted to their O-methyloxime trimethylsilyl derivatives. GC-MS analysis indicated the major metabolic processes to be sequential reduction of the A-ring and hydroxylation at C6 and C16. In the phase II study, unconjugated, beta-glucuronidated and sulfated metabolites were fractionated and deconjugated using a combination of liquid-liquid extraction, enzyme hydrolysis, solid-phase extraction and acid catalysed methanolysis. Derivatization followed by GC-MS analysis revealed extensive conjugation to both glucuronic and sulfuric acids, with only a small proportion of metabolites occurring in unconjugated form.

Comparison of the efficiences of enzymatic and chemical hydrolysis of (nortestosterone and diethylstilboestrol) glucuronides in bovine urine

Residues of 19-nortestosterone (19-NT) and diethylstilboestrol (DES) are excreted in bovine urine, mainly conjugated to glucuronic acid. Prior to quantification, urine must be deconjugated, which is commonly performed by enzymatic or chemical hydrolysis. The efficiencies of two enzymatic and two chemical deconjugation methods were studied. The range of efficiencies obtained for DES were 51.8% (beta-glucuronidase, incubation at 37 degrees C overnight) and 2.7% (methanolic HCl), respectively. Similarly, efficiencies for NT ranged from 43.1% (beta-glucuronidase, incubation at 55 degrees C for 2 h) to 12.7% (methanolic HCl). The results highlight that within control laboratories significant underestimation of drug residue content in samples may occur, due to poor deconjugation.

Analysis of corticosteroids in equine urine by liquid chromatography-mass spectrometry

A liquid chromatography-mass spectrometry (LC-MS) method for the analysis of corticosteroids in equine urine was developed. Corticosteroid conjugates were hydrolysed with beta-glucuronidase; free and enzyme-released corticosteroids were then extracted from the samples with ethyl acetate followed by a base wash. The isolated corticosteroids were detected by LC-MS and confirmed by LC-MS-MS in the positive atmospheric pressure chemical ionisation mode. Twenty-three corticosteroids (comprising hydrocortisone, deoxycorticosterone and 21 synthetic corticosteroids), each at 5 ng/ml in urine, could easily be analysed in 10 min.

The metabolism of norethandrolone in the horse: characterization of 16-, 20- and 21-oxygenated metabolites by gas chromatography/mass spectrometry

After oral administration to a thoroughbred gelding, the anabolic steroid norethandrolone was converted into a complex mixture of oxygenated metabolites. These metabolites were extracted from the urine, deconjugated by methanolysis and converted to their O-methyloxime trimethylsilyl derivatives. Gas chromatographic/mass spectrometric analysis indicated the major metabolites to be 19-norpregnane-3,16,17-triols, 19-norpregnane-3,17,20-triols and 3,17-dihydroxy-19-norpregnan-21-oic acids. Some minor metabolites were also detected.