Determination of β-19-nortestosterone and its metabolite α-19-nortestosterone in biological samples at the sub parts per billion level by high-performance liquid chromatography with on-line immunoaffinity sample pretreatment

Gas chromatographic‐mass spectrometric confirmation of 19‐nortestosterone in the urine of untreated boars — effect of the administration of Laurabolin®

“…The method was validated by spiking urine samples with 17a-19-NT in a concentration of 5 ppb. It proves that, in contrast to what is observed in cattle (2,7,16), C-17 epimerisation is not a major pathway of metabolism of 17p-19-NT in boars.…”

5α-Estrane-3β,17β-diol and 5β-estrane-3α,17β-diol: Definitive screening biomarkers to sign nandrolone abuse in cattle?

“…Efficient control of the illegal use of anabolic steroids must both take into account metabolic patterns and associated kinetics of elimination [6,12,20] to target analytes of interest and appropriate detection windows. Regarding 17␤-NT metabolism, studies have mainly been reported on human subjects [6,12,13,[21][22][23][24][25] but also on horses [26], pigs and bovine animals [27][28][29][30], but in particular calves [27][28][29][30][31][32][33][34][35]. In horses [36][37][38], main reported metabolites observed after 17␤-NT administrations are 17␣-nortestosterone (17␣-NT), 19-noretiocholanolone (NE) but also 19-norandrosterone (NA), which has rarely been observed in cattle.…”

Estranediols profiling in calves’ urine after 17β-nandrolone laureate ester administration

“…Improved analytical sensitivity, leading to increased periods of detection post drug administration, can be achieved in urine using gas chromatography-tandem mass spectrometry (GC-MS/MS) [6][7][8][9] or liquid chromatography-tandem mass spectrometry (LC-MS/MS) [10][11][12][13][14][15]. Efficient control of the illegal use of anabolic steroids must both take into account metabolic patterns and associated kinetics of elimination [5,8,16] which have mainly been reported for 17␤-NT on human subjects [5,8,9,[17][18][19]21] but also on horses [20], pigs and bovine animals [22][23][24][25], in particular calves [22][23][24][25][26][27][28][29]. In horses [30][31][32], main reported metabolites observed after 17␤-NT administrations are 17␣-nortestosterone (17␣-NT), 19-noretiocholanolone (NE) but also 19-norandrosterone (NA), which has rarely been observed in cattle.…”