# Exogenous Versus Endogenous Nandrolone in Doping Investigations: A Systematic Literature Review
## 3 Results
\begin{table}
\begin{tabular}{p{113.8 pt} p{113.8 pt} p{113.8 pt}} \hline \hline
**Authors** & **Analytical Techniques** & **Concentrations Found** \\ \hline [PERSON] et al. (1999) [11] & GC-MS & On a total of 32 urine, 11 had a concentration of 19-NA between the limit of detection (LOD) and 0.3 ng/mL, 7 had concentrations between 0.2 ng/mL and 0.6 ng/mL, and, in 14, it was not detected. 19-NE was not observed above the detection limit (LOD) of the method (0.02 ng/mL). \\ \hline [PERSON] et al. (1999) [12] & GC-MS & Not clearly reported \\ \hline [PERSON] et al. (2000) [13] & LC-MS/MS & Some traces of 19-NA and 19-NE are present in low concentrations in the reference urine (H0), which correspond to the endogenous 19-NA and 19-NE (<0.01 ppb) levels. One hundred and five minutes after meal intake, levels of the two metabolites slightly increased to reach 0.02 and 0.01 ng/mL for 19-NA and 19-NE, respectively. The concentration progressed drastically three hours and fifty minutes after boar ingestion, to attain 3.2 and 0.8 ppb, respectively. Twenty-four hours after meal consumption, the levels returned to the endogenous values, i.e., around 0.1 ppb.For the three individuals, the maximal values reached for 19-NA were 7.5, 3.7, and 3.1 mg/L. For 19-NE, the highest concentrations were 1.0, 0.5, and 1.2 mg/L. \\ \hline [PERSON]. [PERSON] et al. (2000) [14] & HRMS & All urine samples from participants treated with androstenedione contained 19-norandrosterone, while no samples from the no-androstenedione group _did_. Urinary concentrations were averaged from day 1 vs. day 7 measurements; mean 19-NA concentrations in the 100 mg/d and 300 mg/d groups were 3.8 ng 7 mL and 10.2 ng/mL. \\ \hline [PERSON] et al. (2001) [15] & GC-MS/MS & 19-NA was detected in 7 samples at concentrations ranging between 0.2 and 0.5 ng/mL. Traces of 19-NE could only be detected in a sample. \\ \hline [PERSON] et al. (2001) [16] & GC-MS/MS & Of 54 samples, 9 were positive for 19-NA: 22 ng/mL, 14 ng/mL, 8 ng/mL, 4 ng/mL, 6 ng/mL, and 5 ng/mL, while the remaining 3 had concentrations between LOD and LOQ. 7 of these samples were also positive for 19-NE: 6 ng/mL and 6.5 ng/mL, while the other 5 had concentrations between LOD and LOQ. \\ \hline [PERSON] et al. (2001) [17] & GC-MS & 19-NA was detected in all 10 baseline urine samples at concentrations ranging between 1 ng/mL and 14 ng/mL. 19-NE was detected in 4 samples at a concentration range of 2 ng/mL and 7 ng/mL. After metabolic stress, no significative variations were found. \\ \hline [PERSON] et al. (2001) [18] & GC-MS/MS & Out of 358 samples taken after effort, 336 had a 19-NA concentration lower than 0.2 ng/mL and 22 higher than 0.2 ng/mL. Out of 137 samples retrieved before effort, none had 19-NA. Of the same 137 samples retrieved after effort, 129 had a 19-NA concentration lower than 0.2 ng/mL and, in only 8, it was higher than 0.2 ng/mL. \\ \hline [PERSON] et al. (2002) [19] & GC-MS & Baseline urinary 19-NA concentrations varied widely across individuals, from undetectable levels to 0.250 ng/mL. Exhaustive exercise _did_ not significantly increase endogenous nandrolone secretion. \\ \hline [PERSON] et al. (2002) [20] & A quadrupole GC-MS & Before administration, the concentration of 19-NA phase II metabolites was lower than 0.1 ng/mL. After nandrolone administration, the urinary concentrations of 19-Na were between 2 and 10 ng/mL. \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Table showing the analytical techniques used in the works reviewed and the concentrations of 19-NA and 19-NE obtained with them.