Question

2. Naphthalene (shown right) is primarily used as raw material to manufacture ink and dyes. It was also the active ingredient of "mothballs", a household pesticide. Human can be exposed to naphthalene by using the pesticide, from tobacco smoke, from burning coal and oil, or occupationally from industrial manufacturing. It is considered a selective lung toxicant. a. In class, we discussed the major causes of toxicant selectivity to the lung. Name and describe two that would apply to naphthalene (4 pts). b. Draw the bioactive metabolite that would contribute to the toxicity and name its toxic mechanism of action (2 pts). c. If we decreased the amount of glutathione within the cell, how might this affect the toxicity of naphthalene? (2 pts). d. Would you expect naphthalene to exert its toxicity by binding to the Aryl Hydrocarbon Receptor? Why or why not? (2 pts).

Answer 1

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Query On e Naphthalene. (a) v Naphthalene ei a natural constituent of Coaltar Compresey 11% of that material by weight ... 0) Napettralene increases the incidents of chronic Nasal inflammation . (1) due to hapthalene toxics, nature, it causes olfactory epithelial 'Metaplasia. ( It also tauses respiratory epithelial Hyperplasia. O The bioactive Metabolite of Naphthalene is Naphthalene 1,2Oxide. Its toxic Bathway can be shown as naplathalie naphthalen 1,2 dihydroxy-1,2-dihydronaphthaler Dihydrodial dellydrogenase Fito leads couglenti leads n conalent binding of Toxicity e om t met de hetabelites. (c) Naphthalene es Metabolised to highly reactive intermediates that are primarily detoxitied by the Conjugation to Glutathione GSH So if we decrease the amount of Glutathiaue within the celle , then the toxicity of naphthane bwill increase ( d Naphthalene was assessed for the cability to activate transcription via Arylhydrocarbon relebtor CAHR ein an invitiro Luufera- se reporter Assay and wles found no activity. These results that AHR mediated enzymes doust Contribute significantly ito napt thalene biodectination en au intalt anitial s şcanned with: Can Scanner,