Detection and quantification of glucuro- and sulfoconjugated metabolites in human urine following oral administration of xenobiotic 19-norsteroids

Direct detection and quantification of 19-norandrosterone sulfate in human urine by liquid chromatography-linear ion trap mass spectrometry

“…3 shows the extracted ion chromatograms with complete separation of 19-NAS and a compound of lower intensity, displaying a similar full scan MS/MS spectrum. It may be hypothesised that this compound is either 19-noretiocholanolone or 19-norepiandrosterone, two stereoisomers excreted in the urine as sulfate conjugates [10,11]. As the reference compounds were not available, it was therefore not possible to clearly identify the metabolite.…”

“…However, this procedure does not provide detailed information about phase II metabolism that leads to formation of steroid glucuronide and sulfate as main conjugated forms. Nevertheless, the concentration of sulfoconjugates may be obtained indirectly by using deconjugation methods based on acid and enzyme hydrolyses [10][11][12]. It has been found that nandrolone and other norsteroids administered orally are metabolised into 19-norandrosterone, 19-noretiocholanolone and 19-norepiandrosterone (19-NEA; 3␤-hydroxy-5␣-androstan-17-one) [10][11][12].…”

“…Nevertheless, the concentration of sulfoconjugates may be obtained indirectly by using deconjugation methods based on acid and enzyme hydrolyses [10][11][12]. It has been found that nandrolone and other norsteroids administered orally are metabolised into 19-norandrosterone, 19-noretiocholanolone and 19-norepiandrosterone (19-NEA; 3␤-hydroxy-5␣-androstan-17-one) [10][11][12]. The first two are predominantly excreted in urine as glucuronide conjugates whereas the last one is almost exclusively sulfoconjugated.…”

Profiling of 19-norsteroid sulfoconjugates in human urine by liquid chromatography mass spectrometry

“…A three-level calibration curve was used in duplicate to quantify the metabolites in real urine samples. The concentrations of QC used for analyses of real urine samples were selected according to expected concentration levels of sulfo and glucuroconjugates in urine after oral administration of nandrolone precursor [12,13].…”

“…This validation assay performed in terms of trueness, repeatability and intermediate fidelity demonstrated that the method is suitable for direct quantification of 19-NA and 19-NE conjugates at a level of 1 ng mL −1 in human urines. For comparison purpose, it is noteworthy that referenced protocols based on the indirect quantification of 19-NAS and 19-NES levels presented lower quantitative performance in terms of sensitivity and range of quantification [12]. Regarding the use of LC/MS/MS for direct quantification of sulfoconjugates, it has been shown that assessment of 19-NAS at subnanogram mL −1 level could be performed using a SPE multi-step approach [9].…”