Bovine liverslices: A multifunctional in vitro model to study the prohormone dehydroepiandrosterone (DHEA)
Rijk, J.C.W. ; Bovee, T.F.H. ; Peijnenburg, A.A.C.M. ; Groot, M.J. ; Rietjens, I.M.C.M. ; Nielen, M.W.F. - \ 2012
Toxicology in Vitro 26 (2012)6. - ISSN 0887-2333 - p. 1014 - 1021.
prepubertal children - exposure assessment - androgen bioassay - metabolism - expression - rat - estrogens - urine - hepatocytes - microsomes
Biotransformation of inactive prohormones like dehydroepiandrosterone (DHEA) can lead to the formation of potent androgens and subsequent androgenic responses in target tissues. In the present study, precision-cut bovine liver slices were used to study the effects of DHEA on the metabolite, transcript and androgenic activity level. Bovine liver slices were exposed for 6h to various concentrations of DHEA. Changes in androgenic activity of the DHEA containing cell culture media were measured using a yeast androgen bioassay and metabolites were identified using ultra performance liquid chromatography time-of-flight mass spectrometry (UPLC-TOFMS), while gene expression in the DHEA-treated liver slices was examined using bovine microarrays and compared with the profile as obtained with 17ß-testosterone (17ß-T). An increase in androgenic activity was observed in the bioassay upon testing of samples from incubations of DHEA with liver slices and the formation of 4-androstenedione (4-AD), 5-androstene-3ß,17ß-diol, 17ß-T, 7a-hydroxy-DHEA, 7-keto-DHEA and 17a-T could be confirmed by UPLC-TOFMS analysis. Exposure of liver slices to DHEA and the strong androgen 17ß-T resulted in the identification of significantly up- and down-regulated genes and revealed similar gene expression profiles for both compounds. The results indicate that DHEA itself is biologically not very active, but is rapidly converted by the liver slices into the more androgen active compounds 4-AD and 17ß-T. Moreover, the present data highlight the multi-functionality of bovine liver slices as an in vitro bioactivation model, allowing the assessment of androgen activity or gene expression as effect-based endpoints for prohormone exposure.
Fate of hormones and pharmaceuticals during combined anaerobic treatment and nitrogen romoval by partial nitritation-anammox in vacuum collected black water
Graaff, M.S. de; Vieno, N.M. ; Kujawa, K. ; Zeeman, G. ; Temmink, B.G. ; Buisman, C.J.N. - \ 2011
Water Research 45 (2011)1. - ISSN 0043-1354 - p. 375 - 383.
sewage-treatment plants - personal care products - waste-water - activated-sludge - aquatic environment - musk fragrances - surface waters - estrogens - antibiotics - behavior
Vacuum collected black (toilet) water contains hormones and pharmaceuticals in relatively high concentrations (mu g/L to mg/L range) and separate specific treatment has the potential of minimizing their discharge to surface waters. In this study, the fate of estrogens (natural and synthetical hormones) and pharmaceuticals (paracetamol, metoprolol, propranolol, cetirizine, doxycycline, tetracycline, ciprofloxacin, trimethoprim, carbamazepine, ibuprofen and diclofenac) in the anaerobic treatment of vacuum collected black water followed by nitrogen removal by partial nitritation-anammox was investigated. A new analytical method was developed to detect the presence of several compounds in the complex matrix of concentrated black water. Detected concentrations in black water ranged from 1.1 mu g/L for carbamazepine to >1000 mu g/L for paracetamol. Anaerobic treatment was only suitable to remove the majority of paracetamol (>90%). Metoprolol was partly removed (67%) during aerobic treatment. Deconjugation could have affected the removal efficiency of ibuprofen as concentrations even increased during anaerobic treatment and only after the anammox treatment 77% of ibuprofen was removed. The presence of persistent micro-pollutants (diclofenac, carbamazepine and cetirizine), which are not susceptible for biodegradation, makes the application of advanced physical and chemical treatment unavoidable. (C) 2010 Elsevier Ltd. All rights reserved.
The isoflavone content of commercially-available feline diets in New Zealand
Bell, K.M. ; Rutherfurd, S.M. ; Hendriks, W.H. - \ 2006
New Zealand Veterinary Journal 54 (2006)3. - ISSN 0048-0169 - p. 103 - 108.
soy isoflavones - postmenopausal women - phytoestrogens - estrogens - foods - cats - identification - genistein - disease - health
To identify and quantify concentrations of the isoflavones genistein, daidzein, biochanin A and formononetin in commercially-prepared feline diets sold in New Zealand. METHODS: Feline diets (n=138) were collected from supermarkets, pet stores and veterinary clinics in New Zealand. Diets were classified into five categories based on the following criteria: the presence/absence of soy, the presence/absence of non-soy plant material, and dry matter (DM) content. A high performance liquid chromatography (HPLC)-based assay was developed and validated to identify and quantify concentrations of the isoflavones genistein, daidzein, biochanin A and formononetin. RESULTS: Isoflavones were detected in all categories of diet, and at quantifiable concentrations in 104/138 (75%) of the diets tested. More dry diets (127/138; 92%) contained isoflavones at quantifiable concentrations than moist diets (83/138; 60%, p
Preliminary Investigation into the Absorption of Genistein and Daidzein by Domestic Cats (Felis catus)1-3
Bell, K.M. ; Pearce, P.D. ; Ugarte, C.E. ; Hendriks, W.H. - \ 2006
The Journal of Nutrition 136 (2006)7. - ISSN 0022-3166 - p. 2004S - 2006S.
soy isoflavones - adult cats - dietary - bioavailability - estrogens - urine
A new flexible synthesis of (D-homo) sterioids
Sarabèr, F.C.E. ; Groot, Æ. de - \ 2004
Tetrahedron Letters 45 (2004)51. - ISSN 0040-4039 - p. 9431 - 9433.
optically-active steroids - derivatives - carbopalladation - skeletons - estrogens - estrone
A short, flexible and efficient procedure has been developed for the synthesis of C17 substituted steroid skeletons and Dhomo steroid skeletons using a ZnBr2 catalysed coupling of a silyl enol ether containing ring D precursor with a Torgov type reagent, followed by acid catalysed cyclisation of the adducts to (D-homo) steroid skeletons. (C) 2004 Elsevier Ltd. All rights reserved.