title: The effect of in vivo treatment with triiodothyronine on the in vitro synthesis of protein-poly(ADP)-ribose adducts by isolated cardiocyte nuclei and the separation of poly(ADP)-ribosylated proteins by phenol extraction and electrophoresis.
abstract: In vivo treatment of rats with triiodothyronine (30 micrograms/100 g of body weight for 4 consecutive days) inhibited poly(ADP)-ribose polymerase activity of cardiocyte nuclei, but low enzymatic activity of nuclei of noncardiocyte origin remained unaffected. RNA synthesis in cardiocyte nuclei isolated from triiodothyronine-treated rats was augmented. A positive correlation was observed between the degree of inhibition of poly(ADP)-ribose polymerase and cardiac ventricular enlargement in triiodothyronine-treated animals. RNA synthesis in isolated cardiocyte nuclei was inhibited by in vitro poly(ADP)-ribosylation only when cardiocyte nuclei were obtained from triiodothyronine-treated animals. In vitro poly(ADP)-ribosylated proteins were isolated from cardiocyte nuclei by solvent partitioning between phenol and aqueous phases. About 90% of the protein-poly(ADP)-ribose adducts partitioned into the aqueous fraction, and the chain length of polymers in this phase was between medium (n = 4-9) and long (n greater than 32), whereas the phenol phase contained protein-oligomer and monomer adducts. Not only the chain length of oligomers but the nature of modified proteins appeared to participate in determining the partitioning of polymer-protein adducts, and different proteins were separated from the two phases by gel electrophoresis. More than 90% of protein-polymer adducts formed by cardiocyte nuclei were not extracted by 0.25 N HCl, indicating prevalence of nonhistone proteins as polymer acceptors. Gel electrophoresis and near quantitative recovery of adducts in a gel system that protected from degradation of adducts to free polymers confirmed the predominance of nonhistone proteins as main acceptors and demonstrated an artifact of autoradiography that seemed to indicate histone H1 as a significant acceptor. Treatment with triiodothyronine diminished poly(ADP)-ribosylation of certain groups of proteins more than others, implying some degree of selectivity of action of the hormone. Catabolism of the polymer in vitro was not affected by triiodothyronine treatment.
mesh_terms: D000818:Animals; D002467:Cell Nucleus / Q000187:drug effects / Q000378:metabolism*; D006321:Heart / Q000187:drug effects; D007700:Kinetics; D008297:Male; D008970:Molecular Weight; D009206:Myocardium / Q000378:metabolism*; D009244:NAD+ Nucleosidase / Q000037:antagonists & inhibitors*; D009702:Nucleoside Diphosphate Sugars / Q000096:biosynthesis* / Q000378:metabolism*; D011064:Poly Adenosine Diphosphate Ribose / Q000096:biosynthesis* / Q000302:isolation & purification / Q000378:metabolism*; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D014176:Protein Biosynthesis; D011506:Proteins / Q000302:isolation & purification; D051381:Rats; D014284:Triiodothyronine / Q000494:pharmacology*
chemical_list: D009702:Nucleoside Diphosphate Sugars; D000067856:Poly(ADP-ribose) Polymerase Inhibitors; D011506:Proteins; C024857:poly(ADP)-ribosylated proteins; D014284:Triiodothyronine; D011064:Poly Adenosine Diphosphate Ribose; D009244:NAD+ Nucleosidase