The role of silica (14808607) in pulmonary disorders at the cellular level was investigated in rat lung. The effect of exposure to silica inhalation on two cytochrome-P450 dependent enzymes (ethoxycoumarin-deethylase and ethoxyphenoxazone-deethylase) in the lung microsomal fraction was studied in male Sprague-Dawley-rats. Exposure to silica had no statistically significant effect on the induction ratio for either activity. Silica exposure may have caused a diminished level of the constitutive enzyme activity in rat lung tissue. Cytochrome-P450 dependent enzymes in the isolated microsomal fraction from whole lung tissue and in isolated rat lung alveolar type-II cells were also studied. Lung microsomal benzyloxyphenoxazone-deethylase was shown to be a nonpolyaromatic hydrocarbon inducible, metyrapone sensitive activity whereas ethoxyphenoxazone-deethylase was a polycyclic aromatic hydrocarbon inducible, alpha-naphthoflavone sensitive form. The alveolar type- II cytochrome-P450 dependent system was tested for its sensitivity to a known purified macrophage secreted compound, platelet activating factor (PAF). PAF exposure enhanced ethoxyphenoxazone- deethylase activity in whole cells but not in microsomal or sonicated whole cell preparations. The effect of PAF may be mediated through a permeability mechanism or through the reversal of an inhibitory process. The authors conclude that a mediator secreted by activated macrophages can affect a critical detoxication mechanism in another cell type of the alveolar region.
We take your privacy seriously. You can review and change the way we collect information below.
These cookies allow us to count visits and traffic sources so we can measure and improve the performance of our site. They help us to know which pages are the most and least popular and see how visitors move around the site. All information these cookies collect is aggregated and therefore anonymous. If you do not allow these cookies we will not know when you have visited our site, and will not be able to monitor its performance.
Cookies used to make website functionality more relevant to you. These cookies perform functions like remembering presentation options or choices and, in some cases, delivery of web content that based on self-identified area of interests.
Cookies used to track the effectiveness of CDC public health campaigns through clickthrough data.
Cookies used to enable you to share pages and content that you find interesting on CDC.gov through third party social networking and other websites. These cookies may also be used for advertising purposes by these third parties.