Endogenous boldenone-formation in cattle: alternative invertebrate organisms to elucidate the enzymatic pathway and the potential role of edible fungi on cattle's feed

Identification of in vitro metabolites of boldenone using Camel liver microsomes – A HR-LCMS approach

Anabolic steroids are widely abused in animal sports to improve their performance. The present study identifies the possible metabolites of boldenone in camel liver. A high-resolution accurate QE mass spectrometer was used to identify the parent boldenone and its metabolites. To investigate the phase 1 biotransformation of boldenone in camel, sodium phosphate buffer and NADPH were used. Chromatographic separation was carried out on a Thermo Hypersil C18 column using acetonitrile and formic acid as mobile phases. The current study, helped in unequivocal detection of six metabolites (Phase 1) for boldenone. The 17b-boldenone is an 3-oxo-Delta (1), Delta(4)-steroid substituted by an oxo group at position 3 and a beta-hydroxy group at position 17. It is prone to oxidation, which results in three hydroxylated metabolites with protonated parent ion of m/z 303.1954 (C19H27O3)+. Androsta-1,4-diene-3,17-dione [M+H]+ of m/z 285.1848 (C19H25O2+), hydroxyandrosta-1,4-diene-3,17-dione [M+H]+ of m/z 301.1797 (C19H25O3+) in addition to 17-hydroxy-androsta-1-en-3-one [M+H]+ of m/z 289.2162 (C19H29O2+) were also identified. The structures of the detected metabolites were identified based on their accurate mass, fragmentation pattern, and chromatographic retention time. In this research, camel liver was successfully used for in vitro experiments as an alternative to liver microsomes.

1,2-Hydrogenation and Transhydrogenation Catalyzed by 3-Ketosteroid Δ1-Dehydrogenase from Sterolibacterium denitrificans-Kinetics, Isotope Labelling and QM:MM Modelling Studies

Bacteria and fungi that are able to metabolize steroids express 3-ketosteroid-Δ¹-dehydrogenases (KstDs). KstDs such as AcmB form Sterolibacterium denitrificans Chol-1 catalyze the enantioselective 1α,2β-dehydrogenation of steroids to their desaturated analogues, e.g., the formation of 1,4-androstadiene-3,17-dione (ADD) from 4-androsten-3,17-dione (AD). The reaction catalyzed by KstD can be reversed if the appropriate electron donor, such as benzyl viologen radical cation, is present. Furthermore, KstDs can also catalyze transhydrogenation, which is the transfer of H atoms between 3-ketosteroids and 1-dehydrosteroids. In this paper, we showed that AcmB exhibits lower pH optima for hydrogenation and dehydrogenation by 3.5-4 pH units than those observed for KstD from Nocardia corallina. We confirmed the enantiospecificity of 1α,2β-hydrogenation and 1α,2β-transhydrogenation catalyzed by AcmB and showed that, under acidic pH conditions, deuterons are introduced not only at 2β but also at the 1α position. We observed a higher degree of H/D exchange at Y363, which activates the C2-H bond, compared to that at FAD, which is responsible for redox at the C1 position. Furthermore, for the first time, we observed the introduction of the third deuteron into the steroid core. This effect was explained through a combination of LC-MS experiments and QM:MM modelling, and we attribute it to a decrease in the enantioselectivity of C2-H activation upon the deuteration of the 2β position. The increase in the activation barrier resulting from isotopic substitution increases the chance of the formation of d³-substituted 3-ketosteroids. Finally, we demonstrate a method for the synthesis of 3-ketosteroids chirally deuterated at 1α,2β positions, obtaining 1α,2β-d²-4-androsten-3,17-dione with a 51% yield (8.61 mg).

Anabolic Steroids in Fattening Food-Producing Animals—A Review

Simple Summary

Anabolic steroids significantly affect animal tissues and cause morphological and histological changes, which are often irreversible. This issue is currently a very hot topic, as the answers to the questions concerning the health of endangered animals and humans vary greatly from country to country. There is a need to further investigate whether the use of anabolic steroids in animal fattening threatens consumer health and to develop new tools for the detection of anabolic steroids in meat. One possibility for detection could be to observe histological changes in the tissues, which form a typical pattern of anabolic abuse. This review gathered information on the anabolic steroids most commonly used in animal fattening, the legislation governing this issue, and the main effects of anabolics on animal tissues.

Abstract

Anabolic steroids are chemically synthetic derivatives of the male sex hormone testosterone. They are used in medicine for their ability to support muscle growth and healing and by athletes for esthetic purposes and to increase sports performance, but another major use is in fattening animals to increase meat production. The more people there are on Earth, the greater the need for meat production and anabolic steroids accelerate the growth of animals and, most importantly, increase the amount of muscle mass. Anabolic steroids also have proven side effects that affect all organs and tissues, such as liver and kidney parenchymal damage, heart muscle degeneration, organ growth, coagulation disorders, and increased risk of muscle and tendon rupture. Anabolic steroids also have a number of harmful effects on the developing brain, such as brain atrophy and changes in gene expression with consequent changes in the neural circuits involved in cognitive functions. Behavioral changes such as aggression, irritability, anxiety and depression are related to changes in the brain. In terms of long-term toxicity, the greatest impact is on the reproductive system, i.e., testicular shrinkage and infertility. Therefore, their abuse can be considered a public health problem. In many countries around the world, such as the United States, Canada, China, Argentina, Australia, and other large meat producers, the use of steroids is permitted but in all countries of the European Union there is a strict ban on the use of anabolic steroids in fattening animals. Meat from a lot of countries must be carefully inspected and monitored for steroids before export to Europe. Gas or liquid chromatography methods in combination with mass spectrometry detectors and immunochemical methods are most often used for the analysis of these substances. These methods have been considered the most modern for decades, but can be completely ineffective if they face new synthetic steroid derivatives and want to meet meat safety requirements. The problem of last years is the application of “cocktails” of anabolic substances with very low concentrations, which are difficult to detect and are difficult to quantify using conventional detection methods. This is the reason why scientists are trying to find new methods of detection, mainly based on changes in the structure of tissues and cells and their metabolism. This review gathered this knowledge into a coherent form and its findings could help in finding such a combination of changes in tissues that would form a typical picture for evidence of anabolic misuse.

Fractional factorial design-based optimisation and application of an extraction and UPLC-MS/MS detection method for the quantification of phytosterols in food, feed and beverages low in phytosterols

Phytosterols are ubiquitous in plants, as they play an important role in cell membrane stability and as signal transducers. Over the last few decades, scientific interest in phytosterols has significantly increased. Most of the interest has focused on the cholesterol-lowering properties of phytosterols, but they may also interfere with endogenous steroid hormone synthesis. Despite this dual interest in phytosterols, accurate and fully validated methods for the quantification of phytosterols in food and feed samples are scarce. During this study an extraction and detection method for the main free phytosterols (β-sitosterol, campesterol, stigmasterol and brassicasterol) was optimised using a fractional factorial design. Detection was carried out on a UPLC-MS/MS triple stage quadrupole apparatus. The extraction and UPLC-MS/MS detection method was fully validated according to EU Council Decision 2002/657 guidelines and Association of Analytical Chemists (AOAC) MS criteria, reaching all evaluated performance parameter requirements. The individual recoveries ranged between 95 and 104 %. Good results for repeatability and intralaboratory reproducibility (RSD %) were observed (<10 %). Excellent linearity was proven on the basis of determination coefficient (R 2 > 0.99) and lack-of-fit test (F test, alpha = 0.05). The limits of detection (LODs) and lower limits of quantification (LLOQs) in grain matrices were as low as 0.01-0.03 mg per 100 g and 0.02-0.10 mg per 100 g. This method allowed quantification of all main, free phytosterols in different grains (oats, barley, corn, malt) and it was shown that the method can be used for other solid food and feed samples as well, including new matrices such as straw, hay, mustard seeds, grass and yellow peas. Additionally, the method was shown to perform well in liquid samples low in phytosterols such as concentrate-based juices, soft drinks and beers (<5 μg per 100 mL). Graphical Abstract An extraction and detection method for the main free phytosterols (β-sitosterol, campesterol, stigmasterol and brassicasterol) was optimised using a fractional factorial design. Detection was carried out on a UPLC-MS/MS triple stage quadrupole apparatus. The extraction and UPLC-MS/MS detection method was fully validated according to EU Council Decision 2002/657 guidelines and Association of Analytical Chemists (AOAC) MS criteria and applied on different matrices including feed and beverages.

Metabolism study of boldenone in human urine by gas chromatography-tandem mass spectrometry

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.

In vitro simulation of the equine hindgut as a tool to study the influence of phytosterol consumption on the excretion of anabolic-androgenic steroids in horses

Traditionally, steroids other than testosterone are considered to be synthetic, anabolic steroids. Nevertheless, in stallions, it has been shown that β-Bol can originate from naturally present testosterone. Other precursors, including phytosterols from feed, have been put forward to explain the prevalence of low levels of steroids (including β-Bol and ADD) in urine of mares and geldings. However, the possible biotransformation and identification of the precursors has thus far not been investigated in horses. To study the possible endogenous digestive transformation, in vitro simulations of the horse hindgut were set up, using fecal inocula obtained from eight different horses. The functionality of the in vitro model was confirmed by monitoring the formation of short-chain fatty acids and the consumption of amino acids and carbohydrates throughout the digestion process. In vitro digestion samples were analyzed with a validated UHPLC-MS/MS method. The addition of β-Bol gave rise to the formation of ADD (androsta-1,4-diene-3,17-dione) or αT. Upon addition of ADD to the in vitro digestions, the transformation of ADD to β-Bol was observed and this for all eight horses' inocula, in line with previously obtained in vivo results, again confirming the functionality of the in vitro model. The transformation ratio proved to be inoculum and thus horse dependent. The addition of pure phytosterols (50% β-sitosterol) or phytosterol-rich herbal supplements on the other hand, did not induce the detection of β-Bol, only low concentrations of AED, a testosterone precursor, could be found (0.1 ng/mL). As such, the digestive transformation of ADD could be linked to the detection of β-Bol, and the consumption of phytosterols to low concentrations of AED, but there is no direct link between phytosterols and β-Bol.

Formation of Δ(1) and Δ(6) testosterone metabolites by human hepatocytes

The existence of urinary testosterone (T) metabolites conjugated with cysteine has been recently reported. The formation of a ring double bond by a phase I metabolic transformation and the subsequent nucleophilic conjugation with glutathione was proposed as a putative metabolic pathway for the occurrence of these metabolites in urine. The main goal of the present study was to confirm the first step of the postulated pathway. For that purpose, human hepatocyte cells systems were incubated with a pure T standard. The cell culture supernatants were analyzed by liquid chromatography coupled to mass spectrometry using a selected reaction monitoring method. Major T metabolites such as androsterone and 4-androstene-3,17-dione, together with the recently reported Δ(1) and Δ(6) metabolites were simultaneously quantified. The formation of 1,4-androstadien-3,17-dione, 4,6-androstadien-3,17-dione, 17β-hydroxy-4,6-androstadien-3-one and 17β-hydroxy-1,4-androstadien-3-one (boldenone) after incubation of T in hepatocyte cell cultures was demonstrated by comparing the retention times and the ion ratios of the metabolites with those obtained by analysis of commercial standards. Thus, the formation of double bonds Δ(1) and Δ(6) by hepatic phase I metabolism of T was confirmed. Analogously to T, this pathway might also be present in other steroids, opening the possibility of targeting additional biomarkers.

Fungal transformation of androsta-1,4-diene-3,17-dione by Aspergillus brasiliensis

BACKGROUND

The biotransformation of steroids by fungal biocatalysts has been recognized for many years. There are numerous fungi of the genus Aspergillus which have been shown to transform different steroid substances. The possibility of using filamentous fungi Aspergillus brasiliensis cells in the biotransformation of androsta-1,4-diene-3,17-dione, was evaluated.

METHODS

The fungal strain was inoculated into the transformation medium which supplemented with androstadienedione as a substrate and fermentation continued for 5 days. The metabolites were extracted and isolated by thin layer chromatography. The structures of these metabolites were elucidated using (1)H-NMR, broadband decoupled (13)C-NMR, EI Mass and IR spectroscopies.

RESULTS

The fermentation yielded one reduced product: 17β-hydroxyandrost-1,4-dien-3-one and two hydroxylated metabolites: 11α-hydroxyandrost-1,4-diene-3,17-dione and 12β-hydroxyandrost-1,4-diene-3,17-dione.

CONCLUSIONS

The results obtained in this study show that A. brasiliendsis could be considered as a biocatalyst for producing important derivatives from androstadienedione.

Carbon isotope ratios of nandrolone, boldenone, and testosterone preparations seized in Norway compared to those of endogenously produced steroids in a Nordic reference population

Determining the origin of anabolic androgenic steroids (AAS) that also are produced endogenously in the human body is a major issue in doping control. In some cases, the presence of nandrolone and boldenone metabolites might result from endogenous production. The GC-C-IRMS technique (gas chromatography-combustion-isotope ratio mass spectrometry) enables the carbon isotopic ratio (CIR) to be measured to determine the origin of these metabolites. The aim of this study was to use GC-C-IRMS to determine the δ(13) CVPDB values of seized boldenone and nandrolone preparations to decide if the steroids themselves were depleted in (13) C, compared to what is normally seen in endogenously produced steroids. In addition, several testosterone preparations were analyzed. A total of 69 seized preparations were analyzed. The nandrolone preparations showed δ(13) CVPDB values in the range of -31.5 ‰ to -26.7 ‰. The boldenone preparations showed δ(13) CVPDB values in the range of -32.0 ‰ to -27.8 ‰, and for comparison the testosterone preparations showed δ(13) CVPDB values of -31.0 ‰ to -24.2 ‰. The results showed that the values measured in the nandrolone and boldenone preparations were in the same range as those measured in the testosterone preparations. The study also included measurements of CIR of endogenously produced steroids in a Norwegian/Danish reference population. The δ(13) CVPDB values measured for the endogenous steroids in this population were in the range of -21.7 to -26.8. In general, most of the preparations investigated in this study show (13) C-depleted delta values compared to endogenously produced steroids reflecting a northern European diet.