Differential effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on nuclear RNA polymerase activity in the rat liver and thymus

Rabinder N. Kurl, Johan Lund, Lorenz Poellinger, Jan-Ake Gustafsson

Research output: Contribution to journalArticle

10 Scopus citations

Abstract

An increase in RNA polymerase B activity in hepatic cell nuclei was observed after a single intravenous injection of 1 μg/rat of TCDD. The enzyme activity was about 70% above the control value at 1 hr after injection and then declined rapidly. A secondary increase was evident at 24 hr. Prior to the secondary increase in RNA polymerase B activity, there was an increase in RNA polymerase A activity which was about 125% above the control value. The initial increase in RNA polymerase B activity was sensitive to both α-amanitin and actinomycin D injected 30 min before TCDD administration. In the thymus, an increase in RNA polymerase B activity was observed 4 hr after injection (25% above control value) but thereafter it declined and at 24 hr it was about 30% below the control value. RNA polymerase A activity was inhibited as early as 1 hr after injection but had returned to the control value at 4hr and then paralleled RNA polymerase B activity. Thus, TCDD stimulated RNA synthesis in the rat liver but the drug inhibited RNA synthesis in the rat thymus. Since these effects were detected as early as 1 hr after TCDD administration it is proposed that TCDD action requires transcriptional response and that this response may represent a primary site of TCDD action in the cell. The cellular entities or mechanisms which TCDD uses to alter transcription in the cell nucleus remain to be determined.

Original languageEnglish (US)
Pages (from-to)2459-2462
Number of pages4
JournalBiochemical pharmacology
Volume31
Issue number15
DOIs
StatePublished - Aug 1 1982

ASJC Scopus subject areas

  • Biochemistry
  • Pharmacology

Fingerprint Dive into the research topics of 'Differential effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on nuclear RNA polymerase activity in the rat liver and thymus'. Together they form a unique fingerprint.

Cite this