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Regulation of cholesterol metabolism in hepatocytes
Ziková, Kateřina ; Vlachová, Miluše (advisor) ; Zlatohlávek, Lukáš (referee)
This thesis summarizes current data about cholesterol metabolism and its regulation in the liver. First part describes cholesterol transport among tissues by lipoproteins. Second part of this work deals with description of metabolic pathways of cholesterol conversion - how the cells obtain and metabolise cholesterol. Almost all cells can synthesize cholesterol or take it up from the circulation. The cells dispose of abundant cholesterol by several mechanisms - they convert cholesterol to cholesteryl esters that can be stored in lipid droplets; they turn cholesterol into oxysterols that can escape easier from the cell; or they export cholesterol through ATP-binding cassette (ABC) transporters. Specialized tissues (adrenal, gonads) transform cholesterol to steroid hormones. However, only the liver can remove cholesterol from the body in physiologically significant amount - it secretes cholesterol into the bile either directly or after conversion to bile acids. Third section deals with regulation of cholesterol metabolism in hepatocyte. Three transcription factors - sterol regulatory element binding protein (SREBP), liver X receptor (LXR), and farnesoid X receptor (FXR) - play the main role in regulation. Their activities are determined by concentration of cellular cholesterol or its metabolites -...
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Electrochemical Oxidation of Selected Bille Acids in Acetonitrile
Klouda, Jan ; Nesměrák, Karel (advisor) ; Rychlovský, Petr (referee)
The use of voltammetry for determining bile acids and similar compounds is described in literature, but in most cases separation precedes. The goal of this bachelor's thesis was to develop a method for direct determination and identification of seven selected bile acids. The experiments were carried out in non-aqueous medium of acetonitrile using DC voltammetry. As the working electrode a rotating disc platinum electrode and a rotating disc glassy carbon electrode were employed. Platinum electrode proved not to be suitable for this kind of use. The GCE on the other hand showed some potential, but the chemical properties of the bile acids exclude its use in terms of identification.
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Regulation of cholesterol metabolism in hepatocytes
Ziková, Kateřina ; Vlachová, Miluše (advisor) ; Zlatohlávek, Lukáš (referee)
This thesis summarizes current data about cholesterol metabolism and its regulation in the liver. First part describes cholesterol transport among tissues by lipoproteins. Second part of this work deals with description of metabolic pathways of cholesterol conversion - how the cells obtain and metabolise cholesterol. Almost all cells can synthesize cholesterol or take it up from the circulation. The cells dispose of abundant cholesterol by several mechanisms - they convert cholesterol to cholesteryl esters that can be stored in lipid droplets; they turn cholesterol into oxysterols that can escape easier from the cell; or they export cholesterol through ATP-binding cassette (ABC) transporters. Specialized tissues (adrenal, gonads) transform cholesterol to steroid hormones. However, only the liver can remove cholesterol from the body in physiologically significant amount - it secretes cholesterol into the bile either directly or after conversion to bile acids. Third section deals with regulation of cholesterol metabolism in hepatocyte. Three transcription factors - sterol regulatory element binding protein (SREBP), liver X receptor (LXR), and farnesoid X receptor (FXR) - play the main role in regulation. Their activities are determined by concentration of cellular cholesterol or its metabolites -...
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