[Effect of combined glucocorticoids and low density lipoproteins on structural and functional changes in hepatocytes...

The combined action of cortisol and low density lipoproteins (LDL) on the hepatic cell functional activity associated with protein biosynthesis was investigated by biochemical, radioisotope, and ultrastructural methods. The preferential uptake from blood serum of high and low density lipoproteins and glucocorticoids in vivo is enhanced, when residential macrophages are stimulated by prodigiozanum belonging to lipopolysaccharides (LPS). Liver macrophages actively take up colloidal gold (labeled LDL) by receptor-mediated endocytosis. The labels are followed in endosomes and lysosomes of Kupffer cells, and in Disse's space, though there are only single granules in hepatocytes. It is suspected that products of glucocorticoid chemical modification (tetrahydrosubstances) and LDL of limited proteolysis, while entering hepatocytes, may co-operatively activate their nucleolar DNA, that manifests in the increase in nucleolar dimensions and relative volume of granular component in them. In the cytoplasm, the density of ribosomes on the rough ER membranes significantly grows, the relative volume of the smooth ER and the number of primary lysosomes increase. In the co-culture of hepatocytes and Kupffer cells under the combined influence of cortisol, LDL and LPS, the protein biosynthesis considerably accelerates. One may suppose that LDL, on transporting steroid hormones and lipophilic xenobiotics into hepatic cells, may take part in the induction of lysosomal and monooxygenase oxidative system enzymes attributed to smooth ER.