title: Liver growth, biosynthesis of cytidine nucleotides and level of cytochrome P-450 in rat liver after administration of alpha-hexachlorocyclohexane.
abstract: The biosynthesis of cytidine nucleotides and the level of microsomal cytochrome P-450 in intact and regenerating rat liver after repeated administration of alpha-hexachlorocyclohexane (alpha-HCH) were compared. In alpha-HCH treated animals the utilization of [2-14C] orotic acid for the synthesis of cytidine nucleotides is suppressed. In 24-h regenerating liver the incorporation of labelled orotic acid into cytidine nucleotides is markedly activated; the degree of activation is lower in regenerating livers of alpha-HCH treated animals. The changes in the level of cytochrome P-450 vary inversely with the changes in the utilization of [2-14C] orotic acid for the synthesis of cytidine nucleotides. The activity of cytidine triphosphate synthetase of liver cytosol increases shortly after the administration of alpha-HCH; uridine-cytidine kinase is enhanced in the later stages of the drug action. Within 15-45 min after the administration of alpha-HCH the uptake of [U-14 C] cytidine into the liver and its incorporation into RNA cytosine are increased. After the administration of the drug the uptake of [2-14 C] uridine and its incorporation into RNA uracil is also enhanced whereas its utilization for the synthesis of cytidine nucleotides of the acid-soluble extract as well as for the RNA cytosine are suppressed.
mesh_terms: D000818:Animals; D003562:Cytidine / Q000378:metabolism; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism*; D003597:Cytosine Nucleotides / Q000096:biosynthesis*; D001556:Hexachlorocyclohexane / Q000494:pharmacology*; D066298:In Vitro Techniques; D008099:Liver / Q000187:drug effects* / Q000254:growth & development / Q000378:metabolism; D008115:Liver Regeneration / Q000187:drug effects; D008297:Male; D009963:Orotic Acid / Q000378:metabolism; D012313:RNA / Q000378:metabolism; D051381:Rats
chemical_list: D003597:Cytosine Nucleotides; D001556:Hexachlorocyclohexane; D003562:Cytidine; D009963:Orotic Acid; D012313:RNA; D003577:Cytochrome P-450 Enzyme System