title: The action of cordycepin on nascent nuclear RNA and poly(A) synthesis in regenerating liver.
abstract: Following a 5 min pulse of [5- 3H]orotic acid via the protal vein, the specific radioactivity of non-poly(A)heterogeneous nuclear RNA (HnRNA) reaches a peak at 12 h after partial hepatectomy. In contrast, poly(A)-HnRNA was maximally elevated only at 2 h after operation. After intraportal injection of cordycepin (3'-deoxyadenosine) 1 min before [5-3H]orotic acid, a dose-dependent inhibition of nuclear HnRNA and rRNA occurred. Fractionation of HnRNA on poly(U)-Sepharose following 20 mg/kg of cordycepin revealed that a 65% reduction occurred in the labeling of poly(A)-HnRNA while non-polyactivity of UTP in control and cordycepin-treated animals indicated no significant alterations in these parameters. Assessment of poly(A) size using poly(A)-HnRNA annealed with oligo(dT)10 as template primer for Escherichia coli DNA polymerase I, showed that 20 mg/kg of cordycepin inhibited nuclear polyadenylylation by 43%; no alteration in the binding of poly(A)-HnRNA to Millipore filters occurred at this dose of cordycepin. These results indicate that cordycepin is a non-selective inhibitor of nuclear RNA and poly(A)synthesis in regenerating rat liver.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D003839:Deoxyadenosines / Q000494:pharmacology*; D008099:Liver / Q000187:drug effects / Q000378:metabolism*; D008115:Liver Regeneration / Q000187:drug effects*; D009963:Orotic Acid / Q000378:metabolism; D011061:Poly A / Q000096:biosynthesis*; D012313:RNA / Q000096:biosynthesis*; D051381:Rats
chemical_list: D003839:Deoxyadenosines; D011061:Poly A; D009963:Orotic Acid; D012313:RNA