The action of stress hormones on the structure and function of erythrocyte membrane.

The action of a mixture of hormones (cortisol and adrenaline) on erythrocyte membrane during their binding was investigated. Changes in the membrane structure were elucidated by atomic force microscopy; microviscosity of the lipid bilayer and changes in the activity of Na(+),K(+)-ATPase at different concentrations of the hormones in erythrocyte suspension were estimated by the fluorescence method. Cortisol and adrenaline were shown to compete for the binding sites.

Interaction mechanism of anabolic steroid hormones with structural components of erythrocyte membranes.

The interaction of testosterone, androsterone, dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DHEAS) with erythrocyte membranes was studied. It was shown that testosterone and androsterone have a high constant of binding to the membranes (K(b) ≈ 10(6) M(-1)), whereas K(b)'s for DHEA and DHEAS are 2 orders of magnitude lower. Hydrogen bonds and hydrophobic interactions play an important role in binding of anabolic steroids.

Interaction mechanism of cortisol and catecholamines with structural components of erythrocyte membranes.

Nonspecific mechanisms of the stress hormones interaction with erythrocyte membranes were studied by means of atomic force microscopy, fluorescence analysis, and IR spectroscopy. It was shown that stress hormones (cortisol, adrenaline, noradrenaline) can bind to erythrocyte membranes with high affinity (K(b) approximately 10(6) M(-1)). The binding mechanism involves hydrogen bonds and hydrophobic and electrostatic interactions.

Activation of nucleolar DNA expression in hepatocytes by glucocorticoids and high density lipoproteins.

A novel mechanism of protein biosynthesis regulation in liver under the action of reduced forms of steroid hormones (tetrahydrocortisol) and apolipoprotein A-I (apoA-I) is presented. Kupffer cells play an important role in uptake of the cortisol and high density lipoproteins (HDL) as well as in formation of the active complex, tetrahydrocortisol+apolipoprotein A-I (THC-apoA-I). If macrophages are stimulated by lipopolysaccharides (LPS), these processes enhance dramatically, thus causing parallel activation of nucleolar DNA expression and ribosome formation in hepatocytes.

General model to describe the structure and dynamic balance between different human serum lipoproteins and its practical application.

Background: Many dangerous diseases are associated with changes in the concentration of blood lipoproteins (LPs). Thus a fast and accurate method is needed to determine the composition of lipoprotein fractions in human serum.

Material/methods: A comparison of 30 parameters characterizing different LPs in serum from 120 healthy donors and 102 multiple sclerosis patients was carried out using a unique algorithm developed to determine the concentrations of all the main lipids and apolipoproteins in each LP fraction and subfraction.