PHYS 799 Lecture Notes - Lecture 13: Obstructive Lung Disease, Drug Metabolism, Cytochrome P450
23 Apr 2019
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Whether something is toxic or not depends on the dosage. Xenobiotic = exogenous chemical in the environment that can be absorbed into the body. Xenobiotic metabolism has two phases: phase i (hydrolysis, oxidation, reduction) and phase ii (glucoronidation, sulfation, methylation, conjugation w/glutathione) Phase i reactions cytochrome p450 system er of liver mainly, also skin, lungs, gi mucosa. Metabolism may generate ros as byproduct and/or activate xenobiotics into toxins (e. g. carbon tetrachloride, benzo[a]pyrene) Outdoor air pollution: sulfur dioxide, co, ozone, nitrogen dioxide, lead, particulate matter. Ozone from reactions w/nitrogen oxide (car exhaust); generates free radicals which injure cells lining respiratory tract and alveoli. Sulfur dioxide, particles, acid aerosols from burning of coal/oil (power plants); particles. <10um can reach alveoli; phagocytosed and generate an inflammatory reaction. Co from car engines (tunnels/garages), burning of fossil fuels, cigarette smoke; binds to hemoglobin and prevents o2 transport hypoxia and cns depression. Acute poisoning cherry red skin and mucus membranes.
