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. The above mentioned changes and the increase of the atherogenicity coefficient allowed a conclusion to be made that rickets of children is the risk-factor of cardiovascular diseases both in childhood and in the following age periods. It is determined that when the organism is provided with vitamin D3 the latter is transported not only into hepatocytes but also into reticulocytes which are a locus for vitamin D storage. This factor maintains the concentration of active metabolites of vitamin D3 on the physiological level within three months. The provision degree of the fetus and the newborn infants depends on mother's concentration level. However the vitamin D3 exchange varies during the pregnancy period.(ABSTRACT TRUNCATED AT 250 WORDS)