Disposition and elimination of three polychlorinated dibenzofurans in the liver of the rat.
The disposition and elimination of 1,2,3,6,7,8-HxCDF (HxCDF), 1,2,3,7,8-PnCDF (1-PnCDF), and 2,3,4,7,8-PnCDF (4-PnCDF) were studied in liver of female Sprague-Dawley rats after administration of a single oral dose of 3.5-6.3 micrograms/kg. The disposition of these PCDF congeners was structure and vehicle dependent. Administration in peanut oil caused the highest liver retention, compared with administration through the standard diet. Half-lives in liver for 1-PnCDF, 4-PnCDF, and HxCDF were 3.3, 108, and 73 days, respectively. 4-PnCDF showed very high liver retention: greater than or equal to 70% of the dose in the first days after administration. To study kinetic interaction in the liver, mixtures of 1-PnCDF and 4-PnCDF (Experiment I) and of 4-PnCDF and HxCDF (Experiment II) were administered. The presence of 4-PnCDF in Experiment I did not significantly influence the half-life of 1-PnCDF. In Experiment II the estimated half-life of 4-PnCDF was again 108 days, but for HxCDF an increased half-life was found, 156 days. It is concluded that PCDFs with a chlorine substituent(s) adjacent to the oxygen bridge (4- and 6-positions) are eliminated very slowly with t1/2 much greater than that of TCDD.
Van den Berg
M
M
Laboratory of Environmental and Toxicological Chemistry, University of Amsterdam, The Netherlands.
de Jongh
J
J
Eckhart
P
P
Van der Wielen
F W
FW
D000818:Animals; D001572:Benzofurans / Q000493:pharmacokinetics / Q000633:toxicity*; D055598:Chemical Phenomena; D002621:Chemistry; D005260:Female; D008099:Liver / Q000187:drug effects* / Q000378:metabolism; D051381:Rats; D011919:Rats, Inbred Strains
D001572:Benzofurans; C023614:dibenzofuran