Determination of selected bisphenols, parabens and estrogens in human plasma using LC-MS/MS.

In this study, a novel liquid chromatography - tandem mass spectrometry method for the simultaneous determination of bisphenols (BPA, BPS, BPF, BPAF), parabens (methyl-, ethyl-, propyl-, butyl-, benzyl-paraben) and estrogens (estrone, estradiol, estriol) in human plasma is presented. Since all analytes possess the phenolic group, dansyl chloride derivatization was applied in order to gain high sensitivity. The method was validated according to FDA guidelines, and all validation requirements were satisfactory. The lower limits of quantifications were 41.6, 54.9, 43.5 and 150.8pg/mL for BPA, BPS, BPF and BPAF; 172, 149, 171, 134 and 202pg/mL for methyl-, ethyl-, propyl-, butyl- and benzyl-paraben; 10.5, 6.7 and 9.4pg/mL for estrone, estradiol and estriol, respectively. This is the first method allowing the determination of plasma bisphenols, parabens and estrogens in one run, and also the first determination of BPF levels in human plasma. The method was used to examine the plasma levels of healthy normospermic men, where three times higher plasma levels of BPF than BPA were found.

Associations of bisphenol A and polychlorinated biphenyls with spermatogenesis and steroidogenesis in two biological fluids from men attending an infertility clinic.

BACKGROUND: In the testis, steroid hormones play an important role in spermatogenesis, the production of semen, and the maintenance of secondary sex characteristics and libido. They may also play a role as a target for substances called endocrine disruptors (EDs). As yet, however, no complex study has been conducted evaluating the relationships between EDs and the steroid spectrum in the plasma and seminal plasma. OBJECTIVES: To shed more light into mechanisms of EDs and the effects of bisphenol A (BPA) and polychlorinated biphenyls (PCBs) on human spermatogenesis and steroidogenesis. METHODS: We determined BPA and 11 steroids in the plasma and seminal plasma of 191 men with different degrees of fertility, using a newly developed liquid-chromatography mass spectrometry method. Concurrently, plasma levels of 6 congeners of PCBs, gonadotropins, selenium, zinc and homocysteine were measured. Partial correlations adjusted for age, BMI and abstinence time were performed to evaluate relationships between these analytes. RESULTS: Seminal BPA, but not plasma BPA, was negatively associated with sperm concentration (r=-0.198; p=0.009), sperm count (r=-0.178; p=0.018) and morphology (r=-0.160; p=0.044). Divergent and sometimes opposing associations of steroids and BPA were found in both body fluids. The sum of PCB congeners was negatively associated with testosterone, free testosterone, the free androgen index and dihydrotestosterone in plasma. CONCLUSION: BPA may negatively contribute to the final state of sperm quality. Moreover, our data indicate that BPA influences human gonadal and adrenal steroidogenesis at various steps. Environmental levels of PCBs negatively correlated with androgen levels, but surprisingly without negative effects on sperm quality.

Changes in the Concentrations of Corticoid Metabolites--The Effect of Stress, Diet and Analytical Method.

A precisely measured corticoid level is important for decision-making in daily clinical practice. These levels can be influenced in the pre-analytical phase, when the effect of stress, timing, and diet can be important. The aim of this study was to elucidate optimal conditions for blood sampling as well as the choice of analytical methods, which they will be used in measuring of corticoids. By studying ten women, we focused on the influences of the stress of cannulation and a large lunchtime meal on cortisol, cortisone, aldosterone and corticosterone levels. We further compared results of cortisol measurements from RIA and LC-MS/MS. Stress from cannulation caused increase of cortisol, cortisone and corticosterone already, when the cannula was being inserted. This indicates that this increase is stimulated by fear of the blood withdrawing rather, than just by the needle insertion itself. The effect of stress on corticosterone disappeared after an hour, while effect on other corticoids was still apparent. Concerning the lunchtime meal, we found an increase in all measured corticoids between 11 and 12 o'clock. After the food, there were marked decreases in cortisone and aldosterone, while declining levels of cortisol and corticosterone had rather plateaus. We compared cortisol in 90 plasma samples measured by a commercial RIA kit and the LC-MS/MS method. Results from both methods showed a strong correlation (r=0.85). When measuring corticoid metabolites, the chosen analytical method, eliminating stress factors, and precisely timed blood sampling considering the daily rhythm and food intake are critical.

Development and validation of LC-MS/MS method for quantification of bisphenol A and estrogens in human plasma and seminal fluid.

Bisphenol A (BPA) is a widely known endocrine disruptor with estrogenic, antiestrogenic or antiandrogenic properties. BPA could interfere with estrogen metabolism as well with receptor-mediated estrogen actions. Both environmental BPA and estrogens may be traced in body fluids, of which, besides the blood plasma, the seminal fluid is of particular interest regarding their possible interactions in the testis. The method for simultaneously determining BPA and estrogens is then needed, taking into account that their concentrations in these body fluid may differ. Here the method was developed and validated for measurements of BPA, estrone (E1), estradiol (E2) and estriol (E3) in blood plasma and seminal plasma using liquid chromatography-tandem mass spectrometry. Due to the phenolic moiety of all compounds, dansyl chloride derivatization could be used. The analytical criteria of the method with respect to expected concentration of the analytes were satisfactory. The lower limits of quantifications (LLOQ) amounted to 43.5, 4.0, 12.7, 6.7 pg/mL for plasma BPA, E1, E2 and E3, and 28.9, 4.9, 4.5, 3.4 pg/mL for seminal BPA, E1, E2 and E3, respectively. The concentrations of individual steroids differed between body fluids. To the best of our knowledge, this is the first method that enabled the measurement of estrogens and BPA together in one run. The concentrations of E1, E2 and for the first time also of E3 in seminal plasma in normospermic men are reported.

Determination of seven selected neuro- and immunomodulatory steroids in human cerebrospinal fluid and plasma using LC-MS/MS.

Dehydroepiandrosterone (DHEA) and its 7-oxo- and 7-hydroxy-metabolites occurring in the brain are considered neurosteroids. Metabolism of the latter is catalysed by 11ß-hydroxysteroid dehydrogenase (11ß-HSD) which also interconverts cortisol and cortisone. The concurrent metabolic reaction to DHEA 7-hydroxylation is the formation of 16α-hydroxy-DHEA. The LC-MS/MS method using triple stage quadrupole-mass spectrometer was developed for simultaneous quantification of free DHEA, 7α-hydroxy-DHEA, 7ß-hydroxy-DHEA, 7-oxo-DHEA, 16α-hydroxy-DHEA, cortisol and cortisone in human plasma and cerebrospinal fluid (CSF). The method employs 500 µL of human plasma and 3000 µL of CSF extracted with diethyl ether and derivatized with 2-hydrazinopyridine. It has been validated in terms of sensitivity, precision and recovery. In plasma, the following values were obtained: limit of detection: 2-50p g/mL; limit of quantification: 5-140 pg/mL; within-day precision 0.58-14.58%; between-day precision: 1.24-13.89% and recovery: 85-113.2%). For CSF, the values of limit of detection: 2-28 pg/mL; limit of quantification: 6-94 pg/mL; within-day precision; 0.63-5.48%; between-day precision: 0.88-14.59% and recovery: 85.1-109.4% were acquired. Medians and concentration ranges of detected steroids in plasma and CSF are given in subjects with excluded normal pressure hydrocephalus (n=37; 65-80 years). The method enables simultaneous quantification of steroids important for the estimation of 11ß-HSD activity in human plasma and CSF. It will be helpful in better understanding various degenerative diseases development and progression.