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Damage to DNA and activity of nuclear DNA repair and replicative enzymes following N ‐nitrosodiethylamine treatment to rats
Author(s) -
Pasupathy K.,
Bhattacharya R. K.
Publication year - 2000
Publication title -
journal of biochemical and molecular toxicology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.526
H-Index - 58
eISSN - 1099-0461
pISSN - 1095-6670
DOI - 10.1002/1099-0461(2000)14:5<277::aid-jbt6>3.0.co;2-k
Subject(s) - dna polymerase , dna , proliferating cell nuclear antigen , dna repair , biology , dna replication , dna clamp , dna ligase , topoisomerase , enzyme , polymerase , microbiology and biotechnology , dna damage , primer (cosmetics) , nuclear dna , dna polymerase ii , dna polymerase delta , biochemistry , polymerase chain reaction , chemistry , mitochondrial dna , reverse transcriptase , gene , organic chemistry
Continuous administration in the drinking water of hepatocarcinogen N ‐nitrosodiethylamine (NDEA) to male rats (200 mg/L) for 60 days resulted in DNA damage in the form of single strand breaks. The damage, which is measured as a shift in the sedimentation of DNA in alkaline sucrose density gradients, was found to be maximum at the fourth week of treatment, and the sedimentation pattern of DNA was found to return to near normal size by the seventh week of NDEA treatment. Simultaneously, there were perturbations in the nuclear enzymes involved in DNA replication and repair. Activities of DNA polymerase β, DNA ligase, and topoisomerase were found to increase in as early as the first week of NDEA treatment and reached the maximum at the fourth week, and thereafter declined to normal level by the eighth week of treatment. Concomitantly, the activities of DNA polymerase α, DNA primase, and RNA polymerase which were unaltered in the initial period of carcinogen treatment recorded a marked increase after sixth week of NDEA treatment. Results suggest that administration of NDEA inflicts DNA damage, which is manifested as increase in DNA repair enzymes in the initial period and activated DNA replicative enzymes at a later period, indicating the active proliferation of transformed cells. © 2000 John Wiley & Sons, Inc. J Biochem Toxicol 14:277–282, 2000