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.

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.

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.

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.

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 11β-hydroxysteroid dehydrogenase (11β-HSD) which also interconverts cortisol and cortisone. The concurrent metabolic reaction to DHEA 7-hydroxylation is the formation of 16α-hydroxy-DHEA.