[Activation of nucleolar DNA and ribosome biosynthesis in hepatocytes under the effect of glucocorticoids and high density lipoproteins].
The structural bases of cooperative effect of glucocorticoids and HDL brings about the activation of protein biosynthesis in hepatocytes. Using surviving rat liver it was shown that these two compounds together activate the gene expression which was indicated by increased 3H-uridine incorporation into the total RNA pool. The enhanced incorporation of 14C-leucine into proteins in these experiments confirms protein biosynthesis acceleration. With the use of liver perfusion technique it was morphologically demonstrated that the earliest changes in hepatocyte genome take place in nucleoli. The increase of nucleolar dimensions and granular component reflects the activation of ribosomal precursors synthesis. Considerable number of ribosomes in the hepatocyte perinuclear space indicates their active transport across the numerous nuclear membrane pores into the cytoplasm. In the first place and more prominently in hepatocytes the protein synthesis "for export" is stimulated, which was proved by the dynamics of ribosome accumulation on the membranes of endoplasmic reticulum according the perfusion duration. The kupffer cells play a significant role in HDL transcytosis and in the realization of their cooperative effect with glucocorticoids.
Panin
L E
LE
Institute of Biochemistry, Siberian Branch of Russian Academy of Medical Sciences, Novosibirsk.
Maksimov
V F
VF
Korostyshevskaia
I M
IM
D000818:Animals; D002466:Cell Nucleolus / Q000187:drug effects* / Q000235:genetics*; D004247:DNA / Q000187:drug effects*; D005786:Gene Expression Regulation / Q000187:drug effects; D005938:Glucocorticoids / Q000494:pharmacology*; D008075:Lipoproteins, HDL / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects* / Q000502:physiology*; D008297:Male; D051381:Rats; D017208:Rats, Wistar; D012270:Ribosomes / Q000187:drug effects* / Q000502:physiology*
D005938:Glucocorticoids; D008075:Lipoproteins, HDL; D004247:DNA