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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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Hormonal activity in wastewater
Čermáková, Tereza ; Cajthaml, Tomáš (advisor) ; Klusoň, Petr (referee)
Endocrine disruptors are natural or manmade substances which affect hormonal systems of organisms. Biologically relevant concentrations are commonly being detected in the environment. The effluents of wastewater treatment plant present their significant secondary source. Due to their occurence and quantity the interest in mixtures increases. Ecotoxicological assays with genetically modified Saccharomyces cerevisiae were aplied to verify reliability of predictive mathematical models for mixtures of standards (estrone, 17β-estradiol, 17α-ethinylestradiol, estriol, bisphenol A, irgasan, 4-nonylphenol). Chromatographic analysis along with yeast assays were used for the evaluation of real samples of wastewater treatment plant effluents and sediments. Schindler's predictive model and Full logistic model (FLM) were more reliable for predicting the whole dose-response curve compared to Generalized concentration addition (GCA). Predicted values of a parameter EC50 from all three models were comparable to empirical measurements. Three out of four samples exhibited estrogenic activity 0.65 - 1.70 ng/L 17β-estradiol ekvivalent (EEQ) above the limit of detection 0.13 - 0.33 ng/L EEQ. Antiestrogenic activity was detected in one of the samples. Prediction could be carried out only in the case of the sediments...
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Hormone remedies and other endocrine disruptors within the living environment
Pfitzner, Robert ; Podlipná, Radka (advisor) ; Smrček, Stanislav (referee)
The progress of modern society has brought along the issue of environmental contamination with various chemical substances which ensue from all kinds of anthropogenous activity. Among the substances which contaminate the living environment in this way are compounds that influence the endocrine system of an organism by disrupting the physiological function of its endogenous hormones. These compunds are known as endogenous disruptors and alongside certain substances of natural origin they, too, show estrogenic activity. The exogens in question have similar structural features, such as the hormone estrogen, which is why they can interact with estrogenic receptors. The compounds are dangerous in that they can influence biological functions, despite being at very low concentrations. At present, intensive research employing the latest instrumental methods is carried out with the aim of assessing the impact of these compounds on mankind and its living environment. The aim of this bachelor's thesis is to summarise the present knowledge of the impact of endocrine disruptors on the living environment, classify them according to their source and outline the methods of analysis as well as the possibility of their decomposition with the help of biodegradation.
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Influence of estrogens on mammalian sperm.
Šidlová, Adéla ; Šebková, Nataša (referee) ; Hortová, Kateřina (advisor)
For many years, estrogens have been considered typically female sex hormones. It is now certain that they are also very important in the regulation of male reproduction, whether their effect is positive or negative. Endogenous estrogens in mammalian males are an important part of the endocrine system. Estrogens play an important role in the growth and maintenance of bone mass, as well as in the development of germ cells and in the marches of spermatogenesis. Healthy sperm are essential for successful reproduction. Effect of endogenous estrogens is partly involved in the regulation of proper development of sperm. Besides the positive effect of endogenous estrogens, there is also a negative effect of estrogens from the external environment, so-called environmental estrogens. Between environmental estrogens are man-made chemicals, xenoestrogens, which increasingly contaminate the environment. Hazards of these estrogenic substances in nature is hidden in their ability to act as endocrine disruptors, which cause defects in many aspects of mammalian reproduction. With regards to the fact that there are more and more substances in current environment that can interfere with hormonal path of mammalian reproduction, it is important to look at this issue. Reproductive disorders that may be caused by...
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