The problem with which this paper is concerned has as its basis one of the most important properties of the conjugated system of double bonds found in some organic molecules, namely, the ability to exhibit stereoisomerism.

In this master ‘s thesis, catanionic vesicles formed by the pseudo-double-chain complex CTA – DS were investigated from the point of view of microviscosity. Samplesand of cationic vesicles contained 23, 43 and 53 mol. % of cholesterol and the double-chain surfactant DODAC. Cationic vesicles were prepared for visual observation, their stability was determined by DLS and the prepared system was further investigated. Microviscosity was determined from fluorescence anisotropy. To study the outer part of the membrane, laurdan fluorescent probes were used whereas diphenylhexatriene was used for the inner part of the membrane. This method has been proven to be suitable because it reflects the conditions of the membrane. Moreover, a 1,3-bispyrenylpropane probe forming intramolecular excimers was used to study the microviscosity in the vesicle bilayer. The dicyanovinyljulolidine (DCVJ) probe was applied in the case of the molecular rotor technique. It has been shown that in the case of the DCVJ probe, the molecular rotor technique is practically unusable, due to the fact that the probe has a low quantum yield at low temperatures. Also, the excimer formation of P3P probes does not lead to the expected results. The cationic vesicles do not seem to support this formation, as they are too closely related. This type of probe can be used for the selected system with some restrictions.

This diploma thesis is oriented to analysis of physiological effect of synthetic estrogen ethinylestradiol (EE), which represents the main component of steroid-based substance used in hormonal contraception. From wide range of physiologically important protein molecules, which might be effected by this steroid, thesis focuses to the study of the sodium plus potassium activated, magnesium dependent adenosinetriphosphatase (Na+, K+ - ATPase), which is selectively inhibited by cardiac glycosides such as ouabain (g strophantine). Na+, K+ - ATPase represents an important plasma membrane bound enzyme, which catalyzes the active transport of sodium and potassium across plasma membrane. In the first part of this work, Na+, K+ - ATPase was determined by binding of radioactively labeled selective inhibitor of this enzyme [3H]ouabain, used for this purpose. In the second part of this work, plasma membrane fluidity was analyzed by steady-state fluorescence anisotropy of DPH. The effect of EE on [3H]ouabain binding was studied first under in vitro conditions by using human embryonic kidney cells (HEK293) which were cultivated for 24 hours in the presence of EE in tissue culture medium. Second, the effect of EE was also studied under in vivo conditions, by subcutaneous application of EE to the female rats of Wistar...