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Endocrine-disruptive effects of bisphenol A and other representatives of bisphenols
Kromková, Lucia ; Cajthaml, Tomáš (advisor) ; Vítků, Jana (referee)
Xenoestrogens are substances of anthropogenic origin that disrupt the human endocrine system. This work deals with bisphenol A, a substance found in plastics all around us, and its effect on the human reproductive system. As the toxicity of bisphenol A is gradually being proven, its production is regulated by legislation, and therefore bisphenol A is being replaced by other derivatives. This work focuses only on the 7 most widespread bisphenol derivatives - S, F, E, B, AP and AF. The endocrine-disrupting effect of bisphenols is discussed from carefully selected relevant studies with an emphasis on the last 5 years (2018-2023) and compiled into clear tables. It turns out that bisphenol AP has the least endocrine disruption per organism, while bisphenol AF and bisphenol S have the highest. In in vitro and in vivo studies, bisphenol A has different concentrations that influence disruptiveness, which indicates the interaction of bisphenol A with other factors in the organism. The greatest risk to humanity is the proven cocktail effect of bisphenol A and transgenerational transmission. Key words: endocrine disruptors, xenoestrogens, bisphenol A, in vitro, bisphenol derivatives, in vivo
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Significance of androgens of adrenal origin in polycystic ovary syndrome and hirsutism
Varausová, Anežka ; Vítků, Jana (advisor) ; Jansová, Denisa (referee)
The adrenal cortex is the source of a wide range of steroid hormones. Mineralocorticoids, glucocorticoids and, last but not least, androgens are synthesized here. The most abundant adrenal androgen is dehydroepiandrosterone sulfate, whose androgenic potency is not high, but it forms a reservoir in the circulation and can subsequently be metabolized to more potent androgens. Another androgen formed in the adrenal cortex is 11β-hydroxy-androstenedione. This steroid also has low androgenic potency, but its importance lies in the fact that it serves as a precursor of the active androgens - 11-oxygenated derivatives of testosterone and dihydrotestosterone. Besides their high androgenic potency, their relatively high levels in circulation prompt attention to be paid to these steroid hormones in all endocrine disorders where classical androgens are monitored. The determination of these androgens is suggested in polycystic ovary syndrome and idiopathic hirsutism, among others, where it could explain the discrepancy between the intensity of clinical symptoms and testosterone and dihydrotestosterone levels. The aim of this thesis is to review the scientific knowledge on the relationship between 11-oxygenated androgens and the mentioned endocrine disorders. Keywords: steroid, adrenal cortex, androgen,...
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The Impact of Selected Endocrine Disruptors on Human Spermatogenesis
Vítků, Jana ; Hill, Martin (advisor) ; Pohanka, Michal (referee) ; Lapčík, Oldřich (referee)
Steroid hormones in testis play an important role in spermatogenesis, maintenance of the male reproductive tract, production of semen and the maintenance of secondary sex characteristics and libido. They are also discussed as a target for substances called endocrine disruptors (EDs). No complex study was conducted on evaluation of relationships between EDs and steroid spectrum in 2 biological fluids; seminal plasma and plasma. The aim of the PhD. thesis was to develop and validate a method for determination of bisphenol A (BPA) and steroid spectrum in plasma and seminal plasma and to shed more light into mechanisms of ED action and effects of BPA and polychlorinated biphenyls (PCBs) on human spermatogenesis and steroidogenesis. Two new liquid-chromatography mass spectrometry methods for determination of BPA and 11 steroids in plasma and seminal plasma were developed and validated. The methods were used for estimation of analyte concentrations in 191 men with a different degree of fertility. Concurrently, the levels of six congeners of PCBs, gonadotropins, selenium and zinc in plasma were estimated. Partial correlations adjusted for age and BMI were calculated to evaluate relationships between these analytes. Seminal BPA, but not plasma BPA, was negatively associated with sperm concentration...
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The Impact of Selected Endocrine Disruptors on Human Spermatogenesis
Vítků, Jana
Steroid hormones in testis play an important role in spermatogenesis, maintenance of the male reproductive tract, production of semen and the maintenance of secondary sex characteristics and libido. They are also discussed as a target for substances called endocrine disruptors (EDs). No complex study was conducted on evaluation of relationships between EDs and steroid spectrum in 2 biological fluids; seminal plasma and plasma. The aim of the PhD. thesis was to develop and validate a method for determination of bisphenol A (BPA) and steroid spectrum in plasma and seminal plasma and to shed more light into mechanisms of ED action and effects of BPA and polychlorinated biphenyls (PCBs) on human spermatogenesis and steroidogenesis. Two new liquid-chromatography mass spectrometry methods for determination of BPA and 11 steroids in plasma and seminal plasma were developed and validated. The methods were used for estimation of analyte concentrations in 191 men with a different degree of fertility. Concurrently, the levels of six congeners of PCBs, gonadotropins, selenium and zinc in plasma were estimated. Partial correlations adjusted for age and BMI were calculated to evaluate relationships between these analytes. Seminal BPA, but not plasma BPA, was negatively associated with sperm concentration...
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The Impact of Selected Endocrine Disruptors on Human Spermatogenesis
Vítků, Jana
Steroid hormones in testis play an important role in spermatogenesis, maintenance of the male reproductive tract, production of semen and the maintenance of secondary sex characteristics and libido. They are also discussed as a target for substances called endocrine disruptors (EDs). No complex study was conducted on evaluation of relationships between EDs and steroid spectrum in 2 biological fluids; seminal plasma and plasma. The aim of the PhD. thesis was to develop and validate a method for determination of bisphenol A (BPA) and steroid spectrum in plasma and seminal plasma and to shed more light into mechanisms of ED action and effects of BPA and polychlorinated biphenyls (PCBs) on human spermatogenesis and steroidogenesis. Two new liquid-chromatography mass spectrometry methods for determination of BPA and 11 steroids in plasma and seminal plasma were developed and validated. The methods were used for estimation of analyte concentrations in 191 men with a different degree of fertility. Concurrently, the levels of six congeners of PCBs, gonadotropins, selenium and zinc in plasma were estimated. Partial correlations adjusted for age and BMI were calculated to evaluate relationships between these analytes. Seminal BPA, but not plasma BPA, was negatively associated with sperm concentration...
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The Impact of Selected Endocrine Disruptors on Human Spermatogenesis
Vítků, Jana ; Hill, Martin (advisor) ; Pohanka, Michal (referee) ; Lapčík, Oldřich (referee)
Steroid hormones in testis play an important role in spermatogenesis, maintenance of the male reproductive tract, production of semen and the maintenance of secondary sex characteristics and libido. They are also discussed as a target for substances called endocrine disruptors (EDs). No complex study was conducted on evaluation of relationships between EDs and steroid spectrum in 2 biological fluids; seminal plasma and plasma. The aim of the PhD. thesis was to develop and validate a method for determination of bisphenol A (BPA) and steroid spectrum in plasma and seminal plasma and to shed more light into mechanisms of ED action and effects of BPA and polychlorinated biphenyls (PCBs) on human spermatogenesis and steroidogenesis. Two new liquid-chromatography mass spectrometry methods for determination of BPA and 11 steroids in plasma and seminal plasma were developed and validated. The methods were used for estimation of analyte concentrations in 191 men with a different degree of fertility. Concurrently, the levels of six congeners of PCBs, gonadotropins, selenium and zinc in plasma were estimated. Partial correlations adjusted for age and BMI were calculated to evaluate relationships between these analytes. Seminal BPA, but not plasma BPA, was negatively associated with sperm concentration...
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