[The ROS-generating and antioxidant systems in the liver of rats treated with prednisolone and vitamin D3].

The mechanisms of glucocorticoid-induced disturbances of liver function is currently not fully clarified. Vitamin D3 was previously shown to play an important role in the regulation of impaired oxidative metabolism and detoxification function of the liver associated with the effects of hepatotoxic compounds. The study was undertaken to define the intensity of oxidative metabolism in the rat liver and survival of hepatocytes after prolonged prednisolone administration and to assess whether vitamin D3 is capable to counter glucocorticoid-induced changes.

[Immunomodulatory effects of vitamin D3 and bisphosphonates in nutritional osteoporosis in rats].

The aim of this study was to determine the effectiveness of separate and combined administration of vitamin D3 and different forms of bisphosphonate (disodium salt of methylenbisphosphonic acid dihydrate and alendronate) on the function of immune cells in rats with nutritional osteoporosis. It was shown that D-hypovitaminosis leads to reduced 25OHD3, which is a biomarker for vitamin D3 and disturbances of metabolic processes in bone tissue that correlated with osteoporosis manifestation. Immunologic disorders related to nutritional osteoporosis were accompanied by the decrease in phagocytic activity of granulocytes and impaired ability to produce bactericidal oxidants.

[Features of cholecalciferol hydroxylation in the liver of rats in conditions of D-hypervitaminosis and activity of alpha-tocopherol].

It is shown, that hepatocytes contain two (microsomal and mitochondrial) vitamin D3 25-hydroxylase enzymes, which differ as to their activity and function with maximal activity at different concentrations to substrate, namely at 15 microM and 100 microM of vitamin D3, accordingly. Activity of vitamin D3 25-hydroxylase enzymes of hepatocytes is regulated by cholecalciferol and alpha-tocopherol. The general and microsomal vitamin D3 25-hydroxylase enzymes activity of hepatocytes is lowered, but mitochondrial isoform is increased under D-hypervitaminosis conditions.

[Role of vitamin E in regulation of cholecalciferol hydroxylation in hypovitaminosis D and hypervitaminosis D].

It is established, that dose-dependent influence of vitamin E on vitamin D3 metabolism, is conditioned by degree of cholecalciferol sufficiency. Under a condition of D-hypovitaminosis, contents of 25OHD3 in blood serum is 2-fold reduced and vitamin D3 25-hydroxylase enzymes activity increased in rat hepatocytes. Vitamin E (0.

[Content and transportation of Ca(2+) to hepatocytes and lipid content of liver cell membrane structure in experimental diabetes in the rat].

It is proved that at experimental diabetes the calcium content in hepatocytes is disturbed. This disorder is mostly shown in increase of calcium content in hepatocytes and in decrease of accumulation of these ions in mitochondrias. One of the possible reasons of changes at this pathology is the change of lipid content of hepatocytes, mitochondrias and microsomes.

[Physiologic functions of vitamin D3 and its metabolism in the body in normal states and in some pathologies].

In the review there are some results of investigations of the laboratory summarized on the mechanisms of vitamin D3 metabolism and its functioning in organism; investigation of infringement of mineral, lipid and protein metabolic processes with vitamin D3 deficiency and with different pathologies and the ways of their regulation as well as the data about some new high-effective forms of vitamin D3 for their implementation in medicine and agriculture.

[Laboratory of medical biochemistry].

The main research directions of the laboratory: investigation of infringement mechanisms in certain metabolic processes with vitamin D3 deficiency and ways of their regulation; study of mechanisms of vitamin D3 functioning and exchange in organisms in the healthy state and with certain pathologies; elaboration of high-effective preparation forms of vitamin D3 for their implementation in medicine and agriculture. It is proved that a decrease in content of active metabolites of vitamin D3 in case of rickets depends on the process gravity; disturbances in the mineral exchange and formation of cyclic nucleotides, changes in the structure and conformation of the blood plasma proteins, lipoproteins of low and high density, lipids and cellular membrane proteins (especially protein 3 of erythrocyte membranes) are observed. This causes the disturbances in vitamin D3 function and in activity of membrane-bound enzymes.

[Sterols of horse erythrocytes].

Sterols of the whole erythrocytes, hemoglobin, membranes and their protein fractions were studied. Erythrocytes and their components were established to contain, besides cholesterol, other substances of the sterol nature. Cholesterol, 7-dehydrocholesterol and other substances of the cholesterol series are practically completely linked with the lipoproteid fractions of the erythrocyte membrane whereas all sterols found in the native erythrocytes in negligible amounts are bound with hemoglobin.