2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) and 1,2,3,7,8-pentachlorodibenzo-p-dioxin (PCDD) were administered by oral gavage [1 ug/kg/week in corn oil (5 ml/kg)] to female Sprague-Dawley rats for up to six months. Liver and kidney DNA were isolated and the formation of DNA adducts in liver and kidney were determined by the highly sensitive 32p-postlabeling assay procedure. No exposure-related spots associated with TCDD or PCDD covalent DNA adducts were noted on the chromatograms of kidney or liver DNA nucleotides from the rats exposed to the toxins for 2 and 6 months. Corn oil treated animals exhibited the characteristic tissue- and age-specific patterns of 32p-labeled I-spots (Randerath, Reddy and Disher, Carcinogenesis 7, 1615, 1986) which are associated with specific DNA modifications of unknown function. Treatment with either PCDD or TCDD resulted in significant and substantial reduction of the levels of the I-compounds in the liver but not the kidney DNA. Reductions in the amounts of individual hepatic I-compounds ranged from 45-65 and 40-80% in rats treated with TCDD for 2 and 6 months respectively. The effects of PCDD were less marked than those observed for TCDD.
ASJC Scopus subject areas
- Environmental Engineering
- Environmental Chemistry
- Health, Toxicology and Mutagenesis