2,3,4,7,8-Pentabromodibenzofuran

EYES: irrigate opened eyes for several minutes under running water. INGESTION: do not induce vomiting. Rinse mouth with water (never give anything by mouth to an unconscious person). Seek immediate medical advice. SKIN: should be treated immediately by rinsing the affected parts in cold running water for at least 15 minutes, followed by thorough washing with soap and water. If necessary, the person should shower and change contaminated clothing and shoes, and then must seek medical attention. INHALATION: supply fresh air. If required provide artificial respiration.

CDFs cause vomiting and diarrhea, anemia, more frequent lung infections, numbness and other effects on the nervous system, and mild changes in the liver. However, there were no permanent liver changes or definite liver damage found in people who ingested CDFs. (L952)

Halogenated dibenzofurans (PCDFs and PBDFs) bind the aryl hydrocarbon receptor (AhR), which increases its ability to activate transcription in the XRE (xenobiotic resoponse element) promoter region. Specifically AhR binds to the PCDF, translocates it to the nucleus and together with hydrocarbon nuclear translocator (ARNT) and xenobiotic responsive element (XRE) increases the expression of CYP1A1 and aryl hydrocarbon hydroxylase (CYP1B1). AhR signaling also increseases conversion of arachidonic acid to prostanoids via cyclooxygenase-2, alters Wnt/beta-catenin signaling downregulating Sox9 and alters signaling by receptors for inflammatory cytokines. AhR signalling also alters proteasomal degradation of steroid hormone receptors, alters cellular UVB stress response and changes the differentiation of certain T-cell subsets. The resulting AhR mediated activation and alteration leads to body weight loss, cancer and thymic atrophy (characteristic of immune and endocrine disruption) which are common toxic responses to PCDFs and related toxic halogenated aryl hydrocarbons.

No information on the metabolism of dibenzofuran in mammalian organisms was found in the available literature. The bacteria Sphingomonas, Brevibacterium, Terrabacter, and Staphylococcus auricularis degrade dibenzofuran to 2,2',3-trihydroxybiphenyl via dibenzofuran 4,4a-dioxygenase. (L952)