title: [Changes in the RNA-dependent DNA-polymerase activity of retrovirus-like particles in the rat liver during postnatal ontogeny].
abstract: The RNA-dependent DNA-polymerase activity was studied in the postmicrosomal fraction and in the microsomal sediment of the liver of the newborn and adult Wistar rats. In the microsomal sediment of 4-6 day old rats the RNA-dependent DNA-polymerase activity was approximately by one order of magnitude higher than in that of 2 week old and adult rats. In the postmicrosomal fraction of 3 day old rats the RNA-dependent DNA-polymerase activity was also higher, but only by 30-35%, than in that of animals of the other age groups. Particles with density of 1.17 g/ml were found in the microsomal sediment of all studied animals. The characteristic morphology, sensitivity of the particle RNA-dependent DNA-polymerase activity to RNAse and the presence of reverse transcriptase allow for these particles to be referred to as retroviruses. A suggestion is put forward that the high intensity of reverse transcription during the early postnatal period can be due to still continuing processes of cell differentiation and enzymatic imprinting.
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D007181:Inclusion Bodies, Viral / Q000201:enzymology*; D008099:Liver / Q000201:enzymology* / Q000254:growth & development / Q000648:ultrastructure; D008862:Microsomes, Liver / Q000201:enzymology; D012194:RNA-Directed DNA Polymerase / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D012190:Retroviridae / Q000201:enzymology*
chemical_list: D012194:RNA-Directed DNA Polymerase
vernacular_title: Izmenenie RNK-zavisimoĭ DNK-polimeraznoĭ aktivnosti retrovirusopodobnykh chastits pecheni krys v protsesse postnatal'nogo ontogeneza.