TY - JOUR
T1 - Differential effect of 2,3,7,8-tetrachlorodibenzo-p-dioxin on nuclear RNA polymerase activity in the rat liver and thymus
AU - Kurl, Rabinder N.
AU - Lund, Johan
AU - Poellinger, Lorenz
AU - Gustafsson, Jan Åke
N1 - Funding Information:
Acknowledgements-R.N.K. isgratefult o Ekhagastiftelsen and the SwedishI nstitute for fellowships.T his work was supportedb y a grantf rom the SwedishC ancerS ociety.
Copyright:
Copyright 2014 Elsevier B.V., All rights reserved.
PY - 1982/8/1
Y1 - 1982/8/1
N2 - 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.
AB - 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.
UR - http://www.scopus.com/inward/record.url?scp=0019947509&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=0019947509&partnerID=8YFLogxK
U2 - 10.1016/0006-2952(82)90054-5
DO - 10.1016/0006-2952(82)90054-5
M3 - Article
C2 - 7126257
AN - SCOPUS:0019947509
VL - 31
SP - 2459
EP - 2462
JO - Biochemical pharmacology
JF - Biochemical pharmacology
SN - 0006-2952
IS - 15
ER -