Table 1.
Scheduled multiple reaction monitoring for derivatized estrogens.
Table 2.
Assay lower limits of quantification (LLOQ), accuracy, and precision.
Fig 1.
Calibration curves for 6 derivatized estrogen analytes measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS).
(A) estrone, (B) 17β-estradiol, (C) 2-hydroxyestrone, (D) 16α-hydroxyestrone, (E) 2-methoxyestrone, and (F) 4-methoxyestrone. The calibration curve for 2-hydroxyestrone is one order of magnitude higher than the other analytes, because of lower sensitivity for this analyte. Area ratio is calculated by dividing an analyte peak area by the appropriate internal standard (IS) peak area in the same sample.
Fig 2.
Representative chromatograms for 4 derivatized estrogen analytes measured by liquid chromatography-tandem mass spectrometry (LC-MS/MS).
The samples were in neat solution for (A) 17β-estradiol (17β-E2), (B) estriol (E3), (C) 4-hydroxyestradiol (4OH-E2), and (D) 2-methoxyestradiol (2Me-E2). The quantifier transitions of the reference standards are shown in blue (10 pg of each) and the 13C-labeled internal standard transitions are shown in green (2 pg of each). Intensity is measured in counts per second (cps).
Table 3.
Assay recovery %.
Table 4.
Internal standard peak area in each matrix relative to neat solution (%).
Table 5.
Behavioral responses to a Simulated Territorial Intrusion (STI) in wild song sparrows.
Fig 3.
Lack of effect of a 10-min STI on circulating and brain estrogen levels of wild adult male song sparrows during the breeding season.
The bar graphs represent concentrations of (A) E1 and (B) 17β-E2. Values are expressed as the mean ± SEM. n = 10 per group.
Fig 4.
Correlations between estrogens in each brain area in wild adult male song sparrows during the breeding season.
Levels of E1 and 17β-E2 were significantly positively correlated in all brain regions except the VTA. Data were analyzed using Spearman’s rho. Subjects from CON and STI groups are represented with empty and filled circles, respectively. n = 10 per group.