A new approach was developed in order to control testosterone abuse in animal production. A gas chromatographic-combustion-isotope ratio mass spectrometric (GC-C-IRMS) method was used to distinguish the exogenous character from the endogenous character of the main metabolites of testosterone (epitestosterone and etiocholanolone) in cattle urine. This method is based on a comparison between the carbon isotope ratio (13C/12C) of testosterone metabolites and those of testosterone endogenous precursors. After urinary steroid purification, extracts were acetylated with acetic anhydride and injected into the GC-C-IRMS system. In order to validate the method, testosterone enanthate was administered to a 4 year old cow. The 13C/12C isotope ratios of testosterone exogenous metabolites appeared to be significantly different to the 13C/12C precursor ratios and were detected until 3 weeks after the anabolic administration. These preliminary results appear to be promising for the difficult control of natural hormones in livestock.

This paper describes an alternative HPLC method for the determination of testosterone and epitestosterone, which is simple, rapid, selective, sensitive and reproducible. Samples were prepared using a previous enzymatic hydrolysis with liquid-liquid extraction. The determination was carried out on a Hypersil BDS-C18 reversed-phase column with gradient elution and UV absorbance detection (240 nm). The limits of quantification (signal-to-noise ratio = 6) were 20 ng/ml for testosterone and 30 ng/ml for epitestosterone.

A gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) method is described and validated for measurement of delta(13)C values of the acetate derivatives of urinary etiocholanolone and androsterone. The analysis was performed with only 2 mL of urine. The sample preparation consisted of deconjugation with beta-glucuronidase, solid phase extraction, and derivatization with acetic anhydride and pyridine. The within-assay precision of two quality control (QC) urine samples ranged from 0.5 to 2.1 CV%. The between-assay precision in the same QC urines ranged from 1.7 to 3.4 CV%. Administration of testosterone enanthate to a subject resulted in a 6 per thousand decrease in delta(13)C values from -25 per thousand (baseline) to -31 per thousand. Two weeks after testosterone administration was discontinued, the delta(13)C values remained abnormally low while the urine testosterone/epitestosterone (T/E) ratio returned to less than 6. This relatively simple method is useful for rapidly screening a large number of urine samples, including those with T/E <6.

OBJECTIVE

The ratio of urinary testosterone (T) to epitestosterone (EpiT) is used to detect T abuse in sport. Also, plasma or urinary concentrations of EpiT have been measured to assess testicular steroidogenesis during hormonal male contraception. Further investigations are required to evaluate the relative contributions of the testis and adrenal to EpiT production. To this purpose, we have compared basal urinary EpiT glucuronide and plasma EpiT and the response to synthetic adrenocorticotrophic hormone (ACTH) stimulation between eugonadal and hypogonadal men.

METHODS

The basal urinary excretion rate of EpiT glucuronide was determined in 34 eugonadal men. Six men, clinically diagnosed as hypogonadal, and 6 out of the 34 eugonadal men previously described, received an intramuscular injection of synthetic ACTH depot (1 mg) at 0800 h on two consecutive days. Blood samples were collected prior to and then at 1.5, 8, 24, 25.5, 32 and 48 h with respect to the first administration (0 h). 24-h urine specimens were collected from 0800 h on days 1 and 2 (baseline) and 3 and 4 (stimulation).

METHODS

Plasma EpiT, T and cortisol were measured by RIA and urinary EpiT and T, following glucuronide hydrolysis, by gas chromatography-mass spectrometry (extract combines aglycones with a minor amount of urinary free steroids).

RESULTS

Basal excretion rates of EpiT glucuronide in eugonadal men (range: 62-751 nmol/24 h) were considerably greater than in hypogonadal men (range: 3-34 nmol/24 h). Mean basal plasma EpiT in eugonadal men (1.32 +/- 0.08 nmol/l) were greater than in hypogonadal men (0.68 +/- 0.04 nmol/l). In each group, synthetic ACTH stimulation increased plasma cortisol 4-fold. In eugonadal men, plasma and urinary EpiT were unchanged whereas plasma and urinary T glucuronide decreased in response to ACTH. In hypogonadal patients, ACTH increased plasma and urinary EpiT while plasma T remained unchanged.

CONCLUSIONS

The testes are the major source of epitestosterone, the adrenal contribution being relatively modest. Following adrenal stimulation, urinary epitestosterone glucuronide increases considerably in hypogonadal men but this increase is masked in eugonadal men because testicular production is probably suppressed by the ACTH-induced rise in cortisol. Activation of the adrenal cortex results in no change or only a small decrease in the urinary T/EpiT ratio in eugonadal men.

Carbon isotope ratio (CIR) analysis has been routinely and successfully used in sports drug testing for many years to uncover the misuse of endogenous steroids. One limitation of the method is the availability of steroid preparations exhibiting CIRs equal to endogenous steroids. To overcome this problem, hydrogen isotope ratios (HIR) of endogenous urinary steroids were investigated as a potential complement; results obtained from a reference population of 67 individuals are presented herein. An established sample preparation method was modified and improved to enable separate measurements of each analyte of interest where possible. From the fraction of glucuronidated steroids; pregnanediol, 16-androstenol, 11-ketoetiocholanolone, androsterone (A), etiocholanolone (E), dehydroepiandrosterone (D), 5α- and 5β-androstanediol, testosterone and epitestosterone were included. In addition, sulfate conjugates of A, E, D, epiandrosterone and 17α- and 17β-androstenediol were considered and analyzed after acidic solvolysis. The obtained results enabled the calculation of the first reference-population-based thresholds for HIR of urinary steroids that can readily be applied to routine doping control samples. Proof-of-concept was accomplished by investigating urine specimens collected after a single oral application of testosterone-undecanoate. The HIR of most testosterone metabolites were found to be significantly influenced by the exogenous steroid beyond the established threshold values. Additionally, one regular doping control sample with an extraordinary testosterone/epitestosterone ratio of 100 without suspicious CIR was subjected to the complementary methodology of HIR analysis. The HIR data eventually provided evidence for the exogenous origin of urinary testosterone metabolites. Despite further investigations on HIR being advisable to corroborate the presented reference-population-based thresholds, the developed method proved to be a new tool supporting modern sports drug testing procedures.

Longitudinal profiling of urinary steroids was investigated by using a gas chromatography/combustion/isotope ratio mass spectrometry (GC/C/IRMS) method. The carbon isotope ratio of three urinary testosterone (T) metabolites: androsterone, etiocholanolone, 5beta-androstane-3alpha,17beta-diol (5beta-androstanediol) together with 16(5alpha)-androsten-3alpha-ol (androstenol) and 5beta-pregnane-3alpha,20alpha-diol (5beta-pregnanediol) were measured in urine samples collected from three top-level athletes over 2 years. Throughout the study, the subjects were living in Switzerland and were residing every year for a month or two in an African country. (13)C-enrichment larger than 2.5 per thousand was observed for one subject after a 2-month stay in Africa. Our findings reveal that (13)C-enrichment caused by a diet change might be reduced if the stay in Africa was shorter or if the urine sample was not collected within the days after return to Switzerland. The steroids of interest in each sample did not show significant isotopic fractionation that could lead to false positive results in anti-doping testing. In contrast to the results obtained with the carbon isotopic ratio, profiling of urinary testosterone/epitestosterone (T/E) ratios was found to be unaffected by a diet change.

Until now, partial filling micellar EKC-ESI-MS (PF-MEKC-ESI-MS) has seldom been applied for human biomolecules. In this study, determination of three electrically neutral endogenous steroid hormones, namely androstenedione, testosterone, and epitestosterone, by PF-MEKC-ESI-MS was investigated. Since ESI-MS and ESI-MS/MS behaviors of testosterone and epitestosterone proved to be nearly identical, efficient separation of the two compounds was required to obtain reliable identification. The chemical conditions as well as the instrumental parameters affecting the PF-MEKC-ESI-MS analysis were researched. In optimal conditions, ESI-MS showed excellent selectivity, and all the steroids could be identified using SIM. LODs were 0.75-5 microg/mL. The results obtained by PF-MEKC-ESI-MS were compared with those obtained by corresponding PF-MEKC-UV. PF-MEKC-UV provided better resolution, repeatability, and more than ten-fold higher sensitivity, in terms of LODs, than PF-MEKC-ESI-MS. The reasons for this were carefully examined. In comparison with PF-MEKC-UV, PF-MEKC-ESI-MS suffered from greater band broadening owing to the sheath-liquid interface. Resolution was also decreased owing to the elevated capillary temperature. Finally, we discovered that in the analysis of electrically neutral compounds, in-capillary sample concentration by micellar sweeping could be more efficiently utilized in PF-MEKC-UV than in PF-MEKC-ESI-MS.

Growth and development of an embryo or fetus during human pregnancy mainly depend on intact hormone biosynthesis and metabolism in maternal amniotic fluid (AF). We investigated the hormonal milieu in AF and developed a liquid chromatography-tandem mass spectrometry (LC-MS/MS) method for the determination of 14 sulfated and 6 unconjugated steroids in AF. 65 A F samples (male: female = 35: 30) of mid-gestation ranging from 16th week of gestation to 25th week of gestation were analyzed. Reference data of 20 steroid levels in AF of healthy women were provided. 13 sulfated and 3 unconjugated steroids were for the first time quantified in AF by LC-MS/MS. Highest concentrations were found for pregnenolone sulfate (PregS: mean ± SD, 8.6 ± 3.7 ng/mL), 17α-hydroxypregnenolone sulfate (17OHPregS: 4.9 ± 2.0 ng/mL), epitestosterone sulfate (eTS: 7.3 ± 3.6 ng/mL), 16α-hydroxydehydroepiandrosterone sulfate (16OH-DHEAS: 21.5 ± 10.7 ng/mL), androsterone sulfate (AnS: 9.2 ± 7.4 ng/mL), estrone sulfate (E1S: 3.0 ± 3.0 ng/mL), estriol 3-sulfate (E3S: 8.1 ± 4.0 ng/mL) and estriol (E3: 1.2 ± 0.4 ng/mL). Only testosterone (T) showed a significant sex difference (p < 0.0001). Correlations between AF steroids mirrored the steroid metabolism of the feto-placental unit, and not only confirmed the classical steroid pathway, but also pointed to a sulfated steroid pathway.

An isotope dilution mass spectrometry (IDMS) method for the determination of selected endogenous anabolic androgenic steroids (EAAS) in urine by UHPLC-MS/MS has been developed using the isotope pattern deconvolution (IPD) mathematical tool. The method has been successfully validated for testosterone, epitestosterone, androsterone and etiocholanolone, employing their respective deuterated analogs using two certified reference materials (CRM). Accuracy was evaluated as recovery of the certified values and ranged from 75% to 108%. Precision was assessed in intraday (n=5) and interday (n=4) experiments, with RSDs below 5% and 10% respectively. The method was also found suitable for real urine samples, with limits of detection (LOD) and quantification (LOQ) below the normal urinary levels. The developed method meets the requirements established by the World Anti-Doping Agency for the selected steroids for Athlete Biological Passport (ABP) measurements, except in the case of androsterone, which is currently under study.

Background: Epitestosterone [E] has for a long time been considered as a biologically inactive androgen. However, recently a distinct antiandrogenic activity of this naturally occurring endogenous epimer of Testosterone has been demonstrated. Especially the ratios of testosterone/epitestosterone (T/E) seem to be key as inhibition of epitestosterone on androgen activity was postulated. As in autism, a higher androgen activity was implied. We, therefore, suggested higher levels of T/E ratios of children with autism versus children with typical development.

Methods: Urine probes of 22 girls with autism (BMI 18.7 ± 4.3; average age 12.3 ± 3.8 years) and a sample of 51 controls (BMI 17.0 ± 2.6; average age 11.9 ± 4 years), as well as 61 boys with autism (BMI 17.04 ± 2. average age 11.9 ± 2.5 years) and 61 control boys (BMI 17.0 ± 2.6; average age 11.1 ± 3.0 years), were analyzed with gas chromatography mass spectrometry.

Results: The average T/E ratio of all boys with autism was 2.5 ± 1.8 versus 2.4 ± 1.3 in boys with typical development, respectively. No significant difference between boys with autism versus boys with typical development could be detected (p = 0.977). In girls with autism, the average T/E ratio was 1.4 ± 0.9 versus 2.0 ± 1.4 in girls with typical development, whereby a significant difference could be detected (p = 0.0285). Further, polynomial analysis of the third degree were conducted, showing a dependence from age with reasonable coefficients of determination (0.075 < R² < 0.22, all samples).

Discussion: As encompassing steroid hormone analysis are expensive and work-intensive, we hoped to find an easily applicable biomarker to support diagnostics in autism. However, as a relatively small sample of only 22 girls with autism were analyzed and menstrual cycle and pubertal status were only partly controllable through the matching of BMI and age, the question arises if it was an incidental finding. Nevertheless, one suggestion might be that epitestosterone has the effect of a competitive inhibition on the androgen receptor, which would probably help to explain the higher prevalence of autism in boys as compared to girls. Presumably, as no significant difference was detected in boys, this effect might not be as relevant from a steroid hormone perspective, and other effects such as altered 17/20-hydroxylase activity as previously shown in boys and girls with autism seem to have more relevance. Analysis of larger samples, including plenty of metabolites and enzymatic cascades, as well as the role of backdoor pathway activity of androgen synthesis of girls with autism, are demanded in order to validate current findings of altered steroid hormones in autism.

Keywords: gas chromatography-mass spectrometry; steroid metabolism; urine.

Boldenone (BOLD), an anabolic steroid, is likely to be abused in livestock breeding and in sports. Although some of BOLD metabolites in human urine, such as 5β-adrost-1-en-17β-ol-3-one (BM1), have been detected, investigations on their excretion patterns for both genders are insufficient. Moreover, little research on 17α-BOLD glucuronide as a metabolite in human urine has been reported. The aim of this study is to make a contribution to the knowledge of 17β-BOLD metabolism in humans. Three male and three female volunteers were orally administrated with 30mg 17β-BOLD. Urine samples were collected and analyzed with gas chromatography-tandem mass spectrometry. The data proved that 17β-BOLD, BM1, and 17α-BOLD were excreted in urine in both free and glucuronic conjugated forms after administration of 17β-BOLD. For most subjects, the urinary concentrations of BM1 were higher than that of 17β-BOLD. 17α-BOLD was excreted in small amounts. 17α-BOLD, 17β-BOLD, and BM1 were present naturally in urine with low concentrations. Administration of 30mg 17β-BOLD could not influence the excretion profiles of urinary androsterone, etiocholanolone, and testosterone/epitestosterone ratio. There were no differences in BOLD metabolic patterns between man and woman.

The feasibility of freeze-dried urine samples containing doping agents to be used in intercomparison exercises and/or as reference materials has been evaluated. Freeze-dried urine samples containing caffeine, ephedrine derivatives (ephedrine, methylephedrine, norephedrine, pseudoephedrine and norpseudoephedrine), amphetamine derivatives (amphetamine, metamphetamine, 3,4-methylenedioxyamphetamine and 3,4-methylenedioxymethamphetamine) and testosterone and epitestosterone glucuronides have been evaluated. For preparation of the samples, blank urines previously subjected to filtration for clarification were fortified with standard solutions of the corresponding compounds and filtered under sterile conditions. Some aliquots of the sterile liquid samples were used for homogeneity testing, others were stored at -80 degree C for reference purposes, and the rest were subjected to lyophilisation. Freeze-dried urine samples were stored at 4-8 degree C and their stability was assessed for a period up to 18 months. Results obtained showed minimal differences (lower than 5%) between lyophilised and non-lyophilised aliquots (stored at -80 degree C) at all time periods except for amphetamine (up to 18%) and norpseudoephedrine (up to 10%). Nevertheless, such differences remained constant over the entire period of study, indicating that the loss of analytes was due to the initial lyophilisation process. The loss of analytes in freeze-dried samples was due to their volatility. Furthermore, an increase in pH by 1 unit was observed following reconstitution of samples prepared from drug-free urine of commercial origin.

The in vitro metabolism in the uropygial gland of the male quail results into large yields of 5 beta-reduced and/or 17 alpha-hydroxylated metabolites. This metabolism was studied in glands of sexually quiescent quails five days after a single intra-muscular injection of testosterone to the birds. This treatment led to an increased production of inactive metabolites (epitestosterone and its 5 beta-reduced metabolites) and to a decrease of unmetabolized testosterone. Thus testosterone controls its own metabolism and by this way means to modulate its action in the uropygial gland of quail.

Steroid profiling was introduced to determine the endogenous steroid misuse in sports. Thus, screening for the exogenous use of these prohibited substances can be established by monitoring a range of endogenous steroids, which constitute the steroid profile and evaluate their concentrations and ratios against reference values. The steroid profiling is currently based on population statistics. As large interindividual variations exist, athlete biological passport (ABP) analysis is ongoing. This study aimed to identify new biomarker(s) for aromatase inhibitor detection in sports using statistical analysis and adapt the model into ABP analysis.Forty-one Chinese nonathlete volunteers (21 males and 20 females) were administered 3 nonsteroidal aromatase inhibitors (aminoglutethimide, letrozole, and anastrozole) independently. Statistical analysis was performed on 16 steroid profile parameters.After administration, the concentrations of endogenous androgen biomarkers including testosterone (T), epitestosterone, androsterone (AN), etiocholanolone (ETIO), 5α-diol, 5β-diol, and dehydroepiandrosterone were increased, while the level of estrogen was decreased. These biomarkers returned to the baselines levels within 1 month. In females, the concentrations of endogenous biomarkers were affected by nonsteroidal aromatase inhibitors, without a common trend. Three new endogenous biomarkers (AN/estrone, ETIO/estrone, and T/estrone) elevated significantly after treatment. The 3 new models were more sensitive than the World Anti-Doping Agency ratio biomarkers. They were also effective in exponentially weighted moving average chart analysis.Verification experiment demonstrated that the biomarker T/estrone was valid in judging the steroidal aromatase inhibitor abuse. The screening of these new endogenous biomarkers can provide additional parameters to support ABP monitoring and specific information regarding the administered steroids.

The intratesticular testosterone concentration is high during the early postnatal period although the intracellular androgen receptor expression (iAR) is still absent in Sertoli cells (SCs). This study aimed to evaluate the non-classical effects of testosterone and epitestosterone on calcium uptake and the electrophysiological effects of testosterone (1μM) on SCs from rats on postnatal day (pnd) 3 and 4 with lack of expression of the iAR. In addition, crosstalk on the electrophysiological effects of testosterone and epitestosterone with follicle stimulating hormone (FSH) in SCs from 15-day-old rats was evaluated. The isotope (45)Ca(2+) was utilized to evaluate the effects of testosterone and epitestosterone in calcium uptake. The membrane potential of SCs was recorded using a standard single microelectrode technique. No immunoreaction concerning the iAR was observed in SCs on pnd 3 and 4. At this age, both testosterone and epitestosterone increased the (45)Ca(2+) uptake. Testosterone promoted membrane potential depolarization of SCs on pnd 4. FSH application followed by testosterone and epitestosterone reduced the depolarization of the two hormones. Application of epitestosterone 5 min after FSH resulted in a delay of epitestosterone-promoted depolarization. The cell resistance was also reduced. Thus, in SCs from neonatal Wistar rats, both testosterone and epitestosterone act through a non-classical mechanism stimulating calcium uptake in whole testes, and testosterone produces a depolarizing effect on SC membranes. Testosterone and epitestosterone stimulates non-classical actions via a membrane mechanism, which is independent of iAR. FSH and testosterone/epitestosterone affect each other's electrophysiological responses suggesting crosstalk between the intracellular signaling pathways.

This study investigated the effects of resistance training and Eurycoma longifolia Jack supplementation on isokinetic muscular strength and power, Wingate anaerobic power, and testosterone: epitestosterone (T/E) ratio in young males.

Forty young males were weight-matched and assigned into four groups: control (C), Eurycoma longifolia jack (ElJ), resistance training (RT), and Eurycoma longifolia Jack plus resistance training group (ElJ & RT). Participants in ElJ and ElJ & RT groups consumed 200 mg Eurycoma longifolia Jack daily, whereas participants in the C and RT groups consumed placebo capsules daily for 8 weeks. Resistance training program which consisted of 10 different exercises was conducted three times per week for 8 weeks. Participants' isokinetic muscular strength and power, anaerobic power, and urinary TE ratio were measured before and after the intervention period. This is a randomized placebo-controlled intervention study. Paired t-test and one-way analysis of variance were used for statistical analysis.

The mean average power of knee flexion at 300°/s in the RT and ElJ & RT groups was significantly (P < 0.05) higher in the posttest compared with pretest. Wingate relative peak power in the RT group increased significantly (P < 0.05) compared with respective pretest value, whereas peak power in the combined ElJ & RT group was significantly (P < 0.05) higher in posttest compared with pretest. There was no significant difference in T/E ratio between pre- and posttests in all the groups.

The prescribed resistance training program, either with or without ElJ supplementation, improved isokinetic power of the lower limb. Resistance training alone improved relative anaerobic power, whereas combined Eurycoma longifolia Jack and resistance training improved peak power output. ElJ consumption of 200 mg daily for 8 weeks did not affect the urinary T/E ratio.

The UGT2B17 gene deletion polymorphism is known to correlate to urinary concentration of testosterone-glucuronide and hence this genotype exerts a large impact on the testosterone/epitestosterone (T/E) ratio, a biomarker for testosterone doping. The objective of this study was to assess if DNA isolated from athletes' urine samples (n = 713) obtained in routine doping controls could be targeted for genotyping analysis for future integration in the athlete's passport. A control population (n = 21) including both urine and blood DNA was used for genotyping concordance test. Another aim was to study a large group (n = 596) of authentic elite athletes in respect of urinary steroid profile in relation to genetic variation. First we found that the genotype results when using urine-derived DNA did not correlate sufficiently with the genotype obtained from whole blood DNA. Secondly we found males with one or two UGT2B17 alleles had higher T/E (mean 1.63 ± 0.93) than females (mean 1.28 ± 1.08), p˂0.001. Unexpectedly, we found that several male del/del athletes in power sports had a T/E ˃1. If men in power sport exert a different urinary steroid profile needs to be further investigated. The other polymorphisms investigated in the CYP17A1, UGT2B7 and UGT2B15 genes did not show any associations with testosterone and epitestosterone concentrations. Our results show that genotyping using urine samples according to our method is not useful in an anti-doping setting. Instead, it is of importance for the anti-doping test programs to include baseline values in the ABP to minimize any putative impact of genotype. Copyright © 2016 John Wiley & Sons, Ltd.

The newly implemented Steroid Module of the Athlete Biological Passport has improved doping tests for steroids. A biomarker included in this passport is the urinary testosterone glucuronide to epitestosterone glucuronide (T/E) ratio, a ratio greatly affected by a deletion polymorphism in UGT2B17. Suspect urine doping tests are further analyzed with gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS) to determine the origin of the androgen. In this study, we investigated the sensitivity of the steroidal module and the IRMS analysis, in subjects administered with three doses of testosterone enanthate (500, 250, and 125 mg), in relation to the UGT2B17 polymorphism. All subjects carrying the UGT2B17 enzyme reached the traditionally used threshold, a T/E ratio of 4, after all three administered doses, whereas none of the subjects devoid of this enzyme reached a T/E of 4. On the other hand, using the athlete biological passport and IRMS analysis, all three doses could be detected to a high degree of sensitivity. The concentrations of all steroids included in the steroidal module were dose dependently increased, except for epitestosterone which decreased independent of dose. The decrease in epitestosterone was significantly associated with circulatory levels of testosterone post dose (rs =0.60 and p=0.007). In conclusion, these results demonstrate that administration of a single dose of 125-500 mg testosterone enanthate could be detected using the athlete biological passport, together with IRMS. Since IRMS is sensitive to testosterone doping independent of UGT2B17 genotype, also very small changes in the steroidal passport should be investigated with IRMS.

The steroidal module of the Athlete Biological Passport (ABP) has been used since 2014 for the longitudinal monitoring of urinary testosterone and its metabolites in order to identify samples suspicious for the use of synthetic forms of Endogenous Anabolic Androgenic Steroids (EAAS). Samples identified by the module may then be confirmed by Isotope Ratio Mass Spectrometry (IRMS) to clearly establish the exogenous origin of testosterone and/or metabolites in the sample. To examine the detection capability of the steroidal ABP model, testosterone administration studies were performed with various doses and three routes of administration - transdermal, intramuscular and subcutaneous with fifteen subjects for each route of administration. Urine samples were collected before, during, and after administration and steroid profiles were analyzed using the steroidal ABP module in ADAMS. A subset of samples from each mode of administration was also analyzed by IRMS. The steroidal ABP module was more sensitive to testosterone use than population-based thresholds and with high dose administrations there was very good agreement between the IRMS results and samples flagged by the module. However, with low dose administration the ABP module was unable to identify samples where testosterone use was still detectable by IRMS analysis. The testosterone/ epitestosterone (T/E) ratio was the most diagnostic parameter for longitudinal monitoring with the exception of low testosterone excreters for whom the 5α-androstane-3α, 17β-diol/epitestosterone (5αAdiol/E) ratio may provide more sensitivity.

Keywords: T/E; steroidal ABP; testosterone.

Androgenic anabolic steroids are the most misused substances in sports because of their performance-enhancing effects. Often synthetic analogues of endogenously present steroids are administered. To determine their endogenous or exogenous origin, Gas Chromatography Combustion Isotope Ratio Mass Spectrometry (GC-C-IRMS) is used in the field of doping control. Compounds subjected to IRMS analysis must be interference-free, with liquid chromatography fraction collection (HPLC-FC) being the crucial clean-up step. However, this clean-up is challenging, particularly for compounds present at low concentrations in samples with pronounced matrix effects. The compounds of interests for IRMS analyses in doping control are testosterone (T) and its main metabolites (androsterone, etiocholanolone, 5α-androstane-3α,17β-diol, 5β-androstane-3α,17β-diol), epitestosterone, 19-norandrosterone (19-NA), boldenone (B) and its main metabolite (BM), formestane (F) and 6αOH-androstenedione (6aOHADION). Currently, the available methods only deal with a selection of the above-mentioned compounds. Some of these compounds (e.g., 19-NA, B, BM, 6aOHADION) are present in very low concentrations, requiring an extensive and dedicated sample clean-up, and this makes it challenging to develop a universal clean-up procedure. Many of these methods require different and multiple offline HPLC-FC setups, which are labour-intensive and time-consuming. That is problematic during, e.g., large sports events, where reporting time is limited (e.g., 72 h). Therefore, in the current work, we developed a uniform online 2D/3D HPLC-FC method, capable of purifying all relevant target compounds in a single run, leading to the fastest clean-up procedure so far (i.e., 31 min for T and its main metabolites; 46 min for 19-NA, F and 6aOHADION; 48 min for B and BM).

Keywords: Boldenone; Doping control; Isotope ratio mass spectrometry; Multi-dimensional liquid chromatography; Steroids; Testosterone.