HAHs Flashcards
1
Q
what usually dictates the toxicity of HAHs?
A
the more chlorinated the HAH, more persistence and toxic the molecule
2
Q
what is the most toxic HAH?
A
2,3,7,8-tetrachlorodibenzene-para-dioxin (2,3,7,8-TCDD or TCDD)
3
Q
half life of HAHs?
A
7-10 years
4
Q
what is the prototypes of HAHs?
A
TCDD
5
Q
what are the biological effects of HAHs?
A
- wasting syndrome (anorexia)
- thymic atrophy
- chloracne
- hepatotoxicity
- IMMUNE SUPPRESSION
- REPRO TOX
- TERATOGENICITY
- CARCINOGENICITY (non-genotoxic)
- endocrine disruption
- enzyme induction
6
Q
mech of tox of dioxins
A
- receptor specific to TCDD found in cytosol of hepatocytes;–known as aryl hydrocarbon receptor; orphan receptor; TCDD diffuses through cell into cytosol–binds to AhR–>dimerizes IN NUCLEUS and binds to DNA–transcribes CYP1a1, CYP1a2,nqo!,ALDh3a1, ugt1a6, and Gsta1 gene–make good biomarkers of AhR agonist exposure in wildlife
- also uncouples CYP–?produces ROS
7
Q
sources of PAHs
A
combustion of organic material– industrial (smelting);
domestic (municipal incinerators)
motor vehicle exhaust
forst fires–big contributor
tobacco
bbqs
major source in NA–burning wood in fireplaces
8
Q
biochemical effects of HAHs?
A
modulate hormones, receptors, growth factors, and receptors; enzyme induction