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Biomedical subjects

S Poelmans

Publications and source records attributed to S Poelmans.

8 recordsLinked to original sources
PubMed2006

Metabolism of methenolone acetate in a veal calf.

The use of anabolic steroids has been banned in the European Union since 1981. In this study, the metabolism of the anabolic steroid methenolone acetate, was investigated in a male veal calf. After daily oral administration of methenolone acetate, three main metabolites were detected in both urine and faeces samples. Among these metabolites, alpha-methenolone was apparently the main one, but 1-methyl-5alpha-androstan-3,17-diol and 3alpha-hydroxy-1-methyl-5alpha-androstan-17-one were also observed. The parent compound was still detectable in faeces. As a consequence, abuse of methenolone acetate as growth promoter can be monitored by analysing urine and faeces samples. A few days after the last treatment, however, no metabolites were observed. Alpha-methenolone was detectable in urine until 5 days after the last treatment, but in faeces no metabolites were detectable after 3 days.

Anabolic Agents↗
PubMed2006

Testosterone metabolism in Neomysis integer following exposure to benzo(a)pyrene.

Cytochromes P450 (CYPs) are important enzymes involved in the regulation of hormone synthesis and in the detoxification and/or activation of xenobiotics. CYPs are found in virtually all organisms, from archae, and eubacteria to eukaryota. A number of endocrine disruptors are suspected of exerting their effects through disruption of normal CYP function. Consequently, alterations in steroid hormone metabolism through changes in CYP could provide an important tool to evaluate potential effects of endocrine disruptors. The aim of this study was to investigate the potential effects of the known CYP modulator, benzo(a)pyrene (BaP), on the testosterone metabolism in the invertebrate Neomysis integer (Crustacea; Mysidacea). N. integer were exposed for 96 h to 0.43, 2.39, 28.83, 339.00 and 1,682.86 microg BaP L(-1) and a solvent control, and subsequently their ability to metabolize testosterone was assessed. Identification and quantification of the produced phase I and phase II testosterone metabolites was performed using liquid chromatography coupled with multiple mass spectrometry (LC-MS2). Significant changes were observed in the overall ability of N. integer to metabolize testosterone when exposed to 2.39, 28.83, 339.00 and 1,682.86 microg BaP L(-1) as compared to the control animals.

Animals↗
PubMed2006

Biological and chemical approaches for the detection and identification of illegal estrogens in water-based solutions.

The continuous introduction of new products used as growth promoters in animal husbandry, for sports doping and as products for body-building requires residue laboratories to initiate research on developing a strategy for the identification of 'unknown' components. In this study, a strategy is presented for elucidating the identity, the structure and the possible effects of illegal estrogenic compounds in an unidentified water-based solution. To obtain complete information on the composition and activity of the unidentified product, a multidisciplinary approach was needed. A case-study is described with a 'solution X' found during a raid. First, in vivo techniques (animal trials with mice, anatomical and histological research) were combined with in vitro techniques (the yeast estrogenic screen (YES)). In a later stage of the investigation, HPLC-fractionation, liquid chromatography-multiple mass spectrometry (LC-MSn) and gas chromatography-multiple mass spectrometry (GC-MSn) were used. Finally, the identity of 'solution X' was confirmed in a very low concentration range (10 ng/L estrone and 400 ng/l ethinyloestradiol).

Animal Husbandry↗
PubMed2005

Endogenous occurrence of some anabolic steroids in swine matrices.

Following findings of 17beta-19-nortestosterone (150-200 microg kg(-1)) in pigs of unspecified gender imported into the European Union, a study to determine steroid and hormone levels in swine from six age/gender categories (uncastrated 'old' boars, cryptorchids, one intersex, barrows, gilts and sows) was initiated. Indeed, for some hormones there has been a discussion about their being endo- or exogenous. Tissue and urine samples from swine from each of the six categories were obtained in Belgium, France, the Netherlands and the USA. Samples were analysed in three laboratories. Quantitation was obtained for norandrostenedione, 19-nortestosterone and boldenone. The results give a well-documented overview of the status of the presence of these hormones in swine. The data illustrate that uncastrated 'old' boars produce the highest percentage of 'positive' matrices, followed by the cryptorchids. Concentrations in the matrices of the barrows and the gilts are lower. Also, sow matrices contain low amounts of nor-steroids. Furthermore, urine samples from an intersex pig contains a higher concentration of nortestosterone than sows and can therefore be suspected for illegal use of these hormones. Veterinarians taking samples in pig farms for the analysis of hormones need to be aware of the presence and concentrations of these substances in the different categories.

Androstenedione↗
PubMed2005

Androstadienetrione, a boldenone-like component, detected in cattle faeces with GC-MS(n) and LC-MS(n).

Boldenone (1,4-androstadiene-17-ol-3-one, Bol) has been the subject of a heated debate because of ongoing confusion about its endogenous or exogenous origin when detected in one of its forms in faecal or urine samples from cattle. An expert report was recently written on the presence and metabolism of Bol in various animal species. Androstadienedione (ADD) is a direct precursor of 17beta-boldenone (betaBol). It is a 3,17-dione; ssBol is a 17-ol-3-one. Not much is published on 1,4-androstadiene-3,17-diol, which is a 3,17-diol (ADL). If animals were exposed for a longer period to one of these analytes, a metabolic pathway would be initiated to eliminate these compounds. Similar to recent testosterone metabolism studies in the aquatic invertebrate Neomysis integer, ADD, ssBol and ADL could also be eliminated as hydroxymetabolites after exposure. The presence of 11-keto-steroids or 11-hydroxy-metabolites in faecal samples can interfere with a confirmation method by gas chromatography-negative chemical ionization mass spectrometry (GC-NCI-MS), after oxidation of corticosteroids with a double bond in the A-ring (e.g. prednisolone or its metabolite prednisone). The presence of androstadienetrione (ADT) in faecal samples of cattle has never been reported. The origin of its presence can be explained through different pathways, which are presented in this paper.

Adrenal Cortex Hormones↗
PubMed2004

Presence and metabolism of the anabolic steroid boldenone in various animal species: a review.

The review summarizes current knowledge on the possible illegal use of the anabolic steroid boldenone. The presence of' boldenone and metabolites in different animal species and the possibility of the occurrence of endogenous boldenone and metabolites is assessed, as are the methods of analysis used for detection. Different laboratories in the European Union have examined the occurrence of boldenone and its metabolites. The results were discussed at different meetings of a European Commission DG-SANCO Working Party) and summarized in an expert report. The situation of the different laboratories at this time is also covered herein. The overall conclusion of the Working Party was that there was a necessity for further research to distinguish between naturally occurring and illegally used boldenone forms. The confirmation of the presence of boldenone metabolites (free and conjugated forms) in certain matrices of animals is proposed as a marker for the illegal treatment with boldenone.

Anabolic Agents↗
PubMed1984

Erythrocyte swelling after rapid dilution of cryoprotectants and its prevention.

These in vitro studies on canine red blood cells confirm that cell swelling occurs after rapid dilution of Me2SO and glycerol. Cells loaded with a penetrating cryoprotectant in a medium with low Na+, high K+ composition present significantly less swelling after rapid dilution of the cryoprotectant than cells exposed to an electrolyte medium characterized by high Na+, low K+ composition. The osmotic cell stress during rapid dilution of Me2SO can be completely counteracted by the simultaneous use of the nonpenetrating sorbitol during exposure and loading. However, the addition of sorbitol is of no important benefit when glycerol is used as the intracellular cryoprotectant. This is probably due to the slower elution of glycerol. Thus utilizing a perfusion solution containing sorbitol during loading and dilution of Me2SO reduces the osmotic injury and may greatly improve the survival prospects of cryopreserved organs by avoiding "out-flow" block.

Animals↗