title: Hepatic nuclear free and engaged RNA-polymerases in young rats pretreated with 3-methylcholanthrene.
abstract: In 3-methylcholanthrene (3-MC)-pretreated young rats the free and engaged RNA polymerases were investigated in detail both in the nucleolar and nucleoplasmic fractions. Both functional forms of the nucleolar RNA polymerase (A) show a great stimulation. The maximum increase of the free form up to 235% compared with controls is obtained 24 h after 3-MC administration. The engaged fraction reaches its maximum later. The extranucleolar RNA polymerase (B) in its engaged form shows the maximum effect (160%) after 24 h, whereas the free form is at first diminished and later on increases steadily. The activation of RNA polymerase A and the interconversion process between the free and engaged form of RNA polymerase B seem to play a significant role in the 3-MC-mediated induction.
mesh_terms: D000546:Amanitins / Q000494:pharmacology; D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002467:Cell Nucleus / Q000201:enzymology*; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D004790:Enzyme Induction / Q000187:drug effects; D007274:Injections, Intraperitoneal; D008099:Liver / Q000187:drug effects / Q000201:enzymology*; D008748:Methylcholanthrene / Q000494:pharmacology*; D051381:Rats
chemical_list: D000546:Amanitins; D008748:Methylcholanthrene; D012321:DNA-Directed RNA Polymerases