Tocopherol modulates the effects of A23187, verapamil, and phorbol myristate acetate on RNA-polymerase activity of isolated rat liver nuclei.
Preincubation of rat liver nuclei with tocopherol decreased inhibition of RNA-polymerase activity of isolated rat liver nuclei by A23187, verapamil, and phorbol myristate acetate (PMA). In nuclei of vitamin E-deficient rats, A23187, verapamil, and PMA did not inhibit label incorporation into RNA with and without tocopherol. A23187, verapamil, and PMA did not inhibit the activity of nuclei treated with 1% Triton X-100; tocopherol activated RNA synthesis but co-administration of A23187 or verapamil and tocopherol had no effect and the combination of tocopherol and PMA inhibited RNA-polymerase activity by 25%. The effect of the combination of verapamil and PMA in the presence of free tocopherol was different from the effect of these compounds assayed in the presence of the complex of tocopherol with tocopherol-binding protein.
Kapralov
A A
AA
Institute of Physiology, Shevchenko Kiev University, Ukraine.
Petrova
G V
GV
Vasilieva
S M
SM
Donchenko
G V
GV
D000818:Animals; D000001:Calcimycin / Q000494:pharmacology; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002352:Carrier Proteins / Q000378:metabolism; D002467:Cell Nucleus / Q000187:drug effects / Q000201:enzymology; D012321:DNA-Directed RNA Polymerases / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D007476:Ionophores / Q000494:pharmacology; D008099:Liver / Q000187:drug effects* / Q000201:enzymology*; D051381:Rats; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology; D014700:Verapamil / Q000494:pharmacology; D014810:Vitamin E / Q000494:pharmacology*; D014811:Vitamin E Deficiency / Q000201:enzymology
D002121:Calcium Channel Blockers; D002352:Carrier Proteins; D007476:Ionophores; C017763:alpha-tocopherol transfer protein; D014810:Vitamin E; D000001:Calcimycin; D014700:Verapamil; D012321:DNA-Directed RNA Polymerases; D013755:Tetradecanoylphorbol Acetate