Results 131 to 140 of about 3,507,248 (152)

Endogenous origin of norandrosterone in female urine: indirect evidence for the production of 19-norsteroids as by-products in the conversion from androgen to estrogen

Journal of Steroid Biochemistry and Molecular Biology, 2001
Frank H De Jong
exaly   +2 more sources

Determination of the origin of urinary norandrosterone traces by gas chromatography combustion isotope ratio mass spectrometry

Analyst, The, 2006
Ute Mareck, Thomas Piper, Mario Thevis
exaly   +2 more sources

Case Study: Atypical δ13 C values of urinary norandrosterone.

Drug Testing and Analysis, 2018
Isotope ratio mass spectrometry (IRMS) has been established in doping control analysis to identify the endogenous or exogenous origin of a variety of steroidal analytes including the 19-norsteroid metabolite norandrosterone (NorA).
F. Hülsemann, V. Gougoulidis, Thomas Schertel, G. Fusshöller, U. Flenker, T. Piper, M. Thevis   +6 more
semanticscholar   +1 more source

Profiling 19‐norsteroids. I—tandem mass spectrometric characterization of the heptafluorobutyryl ester and pentafluorobenzyloxime heptafluorobutyryl ester derivatives of 19‐nortestosterone using collisionally activated dissociation

Journal of Mass Spectrometry, 1995
AbstractTandem mass spectrometric methods for the identification of 19‐nortestosterone (estr‐4‐en‐17β‐3‐one) are described and evaluated. The fragmentation reactions of the heptafluorobutyryl (HFB) and pentafluorobenzyloxime heptafluorobutyryl (PFBOHFB) ester derivatives of 19‐nortestosterone in particular were studied for the purpose to select ...
D. de Boer, S. N. Bensink, A. R. Borggreve, R. D. van Ooijen, R. A. A. Maes   +4 more
openaire   +1 more source

Modulation of phase II metabolism: A case study on 19-norandrosterone

2014
19-norandrosterone is the main phase I metabolite of the synthetic androgenic anabolic steroid (AAS) 19-nortestosterone (or nandrolone). Once formed 19-norandrosterone undergoes conjugation reaction catalyzed mainly by the uridine diphospho glucuronosyltransferases (UDPGTs) to form the corresponding glucuro-conjugated. Due to the fact that the presence
Mazzarino, M, Alessi, B, de la Torre, X, Fiacco, I, PALERMO, AMELIA, BOTRE', Francesco   +5 more
openaire   +4 more sources

Nandrolone criteria for 19-norandrosterone Isotope Ratio Mass Spectrometric confirmation

2014
The detection of the use of nandrolone and other 19-norsteroids is based primarily upon the identification of the main urinary metabolite, 19-norandrosterone (19-NA) in a concentration (derived from hydrolysis with β-glucuronidase) greater than the Decision Limit (DL), as established in the DL Technical Document.
X. de la Torre, C. Colamonici, D. Curcio, A. Beotra, S. Jain, T. Kaur, A. Shrivastava, BOTRE', Francesco   +7 more
openaire   +2 more sources

GC-ion trap-MS in doping control: urinary determination of 19-norandrosterone and 19-noretiocholanolone at subnanogram per millilitre levels

2002
A specific and sensitive method was developed for the quali-quantitative determination in urine of 19- norandrosterone (19-NA) and 19-noretiocholanolone (19-NE), main metabolites of the anabolic androgenic steroid nandrolone as well as of other 19-norsteroids. The total steroid fraction, extracted from urine, after addition of Ds-noretiocholanolone, by
Tedeschi L, FAVRETTO, DONATA, Frison G, Maietti S, CASTAGNA, FRANCA, FERRARA, SANTO   +5 more
openaire   +1 more source

PRESENCE OF ILLICIT DRUG METABOLITES IN THE INFLUENT OF A WASTEWATER TREATMENT PLANT IN ELDORET, KENYA

International Research Journal of Rongo University
The increased occurrence of illicit and medical drug residues in urban wastewater raises new environmental and public health problems. Conventional monitoring methods are frequently expensive, invasive, and have limited population coverage, rendering ...
John Kevine Ochieng, F. O. Olal, Edward Anino   +2 more
semanticscholar   +1 more source

Prevalence of nandrolone preparations with endogenous carbon isotope ratios in Australia.

Drug Testing and Analysis
Nandrolone and its prohormones, including 19-norandrost-4-ene-3,17-dione and 19-norandrost-4-ene-3β,17β-diol, are anabolic steroids forbidden at all times in sports according to the World Anti-Doping Code Prohibited List and its metabolite 19 ...
M. Polet, P. Van Eenoo, L. Brooker, C. Edey, Vanessa Agon, J. Grainger, G. Payne, C. Goebel   +7 more
semanticscholar   +1 more source

Detecting the abuse of 19‐norsteroids in doping controls: A new gas chromatography coupled to isotope ratio mass spectrometry method for the analysis of 19‐norandrosterone and 19‐noretiocholanolone

Drug Testing and Analysis, 2021
Xavier de la Torre, Francesco Botre, Loredana Iannella   +2 more
exaly