instrumental techniques applied to mineralogy and geochemistry

102 Clemente Recio
following administration of 19-norandrostanedione the 13 C value of urinary 19Na
decreased relative to PD (Fig. 8, bottom). IRMS analysis of the doping agent returned a
lower abundance of 13 C ( 13 C PDB of 19-norandrostanedione equalled -32.8 ±0.3‰) than
endogenous 19Na. As a result, it appears that oral administration of the doping agent
altered the isotopic value of the steroid's metabolites, yet left the steroid precursors
unchanged.
Base Line
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Pregnanediol
19-Norandrostereone
1 2 3 4 5 6
Volunteer
48 Hrs after oral administration of 100 mg of 19-Norandrostanedione
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1 2 3 4 5 6
Volunteer
Pregnanediol
19-Norandrostereone
FIGURE 8. Evolution of the 13 C value of urinary steroids before and 48 hrs. after
administration of 19-norandrostanedione. Data from Phillips et al. (2000).
Urine from pregnant women in their third trimester were also analysed and the 13 C
values were very much the same as those of the volunteers prior to nandrolone
administration, yet it is known that at this stage in their pregnancy, women can show
large increases in concentration of urinary 19Na. The data shows that the IRMS analysis