As. Clouet et al., IDENTIFICATION OF ENDOGENOUS 19-NORTESTOSTERONE IN PREGNANT EWES BY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY, Analyst, 122(5), 1997, pp. 471-474
Considered as a xenobiotic for many years, 19-nortestosterone has been
extensively studied, Analyses developed to control the illegal use of
this steroid in meat-producing animals led researchers to demonstrate
the endogenous presence of 19-nortestosterone in several species, In
this paper, the natural occurrence of 19-nortestosterone in its alpha
form (epinandrolone) in the urine of pregnant sheep was demonstrated u
sing gas chromatography-mass spectrometry, This reference method allow
ed 17 alpha-nandrolone to be detected and identified, and the absence
of the beta epimer in the urine of pregnant sheep to be demonstrated,
17 alpha-Nandrolone was accurately determined at different stages of p
regnancy, The analyses showed that epinandrolone, which was not detect
able in the urine of non-pregnant sheep, was excreted in small amounts
(leading to a < 0.5 ppb concentration) during the first 4 months of p
regnancy, 17 alpha-Nandrolone concentrations then increased during the
last month until parturition, The origin of this molecule was not det
ermined.