Figure 1.
Metabolome analysis reveals time-dependent metabolic effect of testosterone over a 12-month period. (A) RBC samples were taken from adolescent patients (N = 15) at baseline and 1 and 12 months after starting testosterone. (B) A line plot of the data normalized to 0 months revealed various descriptive variables that changed over time. (C) A principal component analysis revealed distinct clustering patterns between the baseline, 1-month, and 12-month timepoints. (D) A variable importance in projection (VIP) plot suggested that acylcarnitines as well as metabolites from glycolysis and the trichloroacetic acid (TCA) were most influential in the PLS-DA clustering pattern. (E) Pathway analysis revealed the pathways most affected by treatment duration. (F) A Spearman rank order correlation of the normalized data determined the top significant correlates to testosterone duration (P ≤ .05). (G) A line plot of diphosphoglycerate (DPG) shows that it increases over treatment duration (mean± standard error of the mean). Testosterone alters the global metabolome. (H) Hierarchal clustering analysis of the top 50 most significant metabolites by analysis of variance revealed time-dependent changes in acylcarnitines, glycolysis, and purine metabolism. (I) Separate clustering by C-means uncovered 3 groups of metabolites with distinct time-dependent trends that support the analysis of variance findings. (J) An elemental inductively coupled plasma-mass-spectrometry analysis was performed on RBC samples (N = 15) to determine cation levels. (K) Line plots revealed ion-specific trends over testosterone duration (mean ± standard error of the mean). LDL, low-density lipoprotein; PLS-DA, partial least squares discriminant analysis.