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Disposition of phenolic and sulfated metabolites after inhalation exposure to 4-chlorobiphenyl (PCB3) in female rats
Journal article   Open access   Peer reviewed

Disposition of phenolic and sulfated metabolites after inhalation exposure to 4-chlorobiphenyl (PCB3) in female rats

Kiran Dhakal, Eric Uwimana, Andrea Adamcakova-Dodd, Peter S Thorne, Hans-Joachim Lehmler and Larry W Robertson
Chemical research in toxicology, Vol.27(8), pp.1411-1420
08/18/2014
DOI: 10.1021/tx500150h
PMCID: PMC4137987
PMID: 24988477
url
https://doi.org/10.1021/tx500150hView
Published (Version of record) Open Access

Abstract

PCBs, such as PCB3, are air contaminants in buildings and outdoors. Metabolites of PCB3 are potential endocrine disrupting chemicals and genotoxic agents. We studied the disposition of phenolic and sulfated metabolites after acute nose-only inhalation exposure to airborne PCB3 for 2 h in female rats. Inhalation exposure was carried out in three groups. In the first group, rats exposed to an estimated dose of 26 μg/rat were euthanized at 0, 1, 2, and 4 h after exposure. Highest concentrations of phenols and sulfates were observed at 0 h, and the values were 7 ± 1 and 560 ± 60 ng/mL in serum, 213 ± 120 and 842 ± 80 ng/g in liver, 31 ± 27 and 22 ± 7 ng/g in lung, and 27 ± 6 and 3 ± 0 ng/g in brain, respectively. First-order serum clearance half-lives of 0.5 h for phenols and 1 h for sulfates were estimated. In the second group, rats exposed to an estimated dose of 35 μg/rat were transferred to metabolism cages immediately after exposure for the collection of urine and feces over 24 h. Approximately 45 ± 5% of the dose was recovered from urine and consisted mostly of sulfates; the 18 ± 5% of the dose recovered from feces was exclusively phenols. Unchanged PCB3 was detected in both urine and feces but accounted for only 5 ± 3% of the dose. Peak excretion of metabolites in both urine and feces occurred within 18 h postexposure. In the third group, three bile-cannulated rats exposed to an estimated dose of 277 μg/rat were used for bile collection. Bile was collected for 4 h immediately after 2 h exposure. Biliary metabolites consisted mostly of sulfates, some glucuronides, and lower amounts of the free phenols. Control rats in each group were exposed to clean air. Clinical serum chemistry values, serum T4 level, and urinary 8-hydroxy-2'-deoxyguanosine were similar in treated and control rats. These data show that PCB3 is rapidly metabolized to phenols and conjugated to sulfates after inhalation and that both of these metabolites are distributed to liver, lungs, and brain. The sulfates elaborated into bile are either reabsorbed or hydrolyzed in the intestine and excreted in the feces as phenols.
Deoxyguanosine - urine Half-Life Rats Thyroxine - blood Chromatography, High Pressure Liquid Environmental Pollutants - metabolism Biphenyl Compounds - metabolism Rats, Sprague-Dawley Tissue Distribution Tandem Mass Spectrometry Animals Feces - chemistry Environmental Pollutants - chemistry Time Factors Inhalation Exposure Sulfates - chemistry Female Phenols - chemistry Biphenyl Compounds - chemistry Deoxyguanosine - analogs & derivatives ISRP Project 1 2015-2020 Inhalation Toxicology Core Synthesis Core

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