CARBON TETRACHLORIDE-INDUCED CHANGES IN MIXED-FUNCTION OXIDASES AND MICROSOMAL CYTOCHROMES IN RAT LUNG

  • 1 January 1977
    • journal article
    • research article
    • Vol. 36  (4) , 388-394
Abstract
The effects of a single exposure, by gastric intubation or inhalation, to CCl4 on rat lungs were assessed. By 1-7 days, focal areas of alveolar collapse, septal edema and modification of type II pneumonocytes were observed. By 24 h after exposure there were no identifiable changes in surfactant levels or distribution. Microsomes obtained from the lungs and prepared for analysis revealed marked decreases in cytochrome P-450 content and P-450-related N-demethylation of dimethylaniline. Only a transient reduction of cytochrome b5 occurred, with a rebound exceeding control values during the period of pulmonary healing. Whether the lung acted as an excretory route (following intubation) or as an absorption path (after inhalation) made little difference. CCl4 had no effect on in vitro microsome composition and function unless supplemented with a NADPH generating system. Under these circumstances, there was a reduction in both cytochromes b/5 and P-450. A considerable chemical modification of the pulmonary tissues had taken place, with no accompanying easily recognized changes in cellular structure. Evidence for the in vitro destruction of pulmonary microsomal cytochromes P-450 and b5, unrelated to peroxidation, is indicated.