The effects of cigarette smoke on the fate of arachidonic acid in rat and hamster lungs.

The effects of cigarette smoke on the fate of exogenous arachidonic acid (AA) were investigated in isolated perfused rat and hamster lungs. 14C-arachidonate was infused into the pulmonary circulation and the metabolites in the effluent as well as the distribution of radiolabel in lung lipids were analysed. Pre-exposure of animals to cigarette smoke daily for three weeks did not change the amounts of metabolites in lung effluent or the incorporation of AA into lung lipids. Cigarette smoke ventilation of lungs from pre-exposed hamsters changed the amounts of some metabolites of AA in the effluent. The distribution of radioactivity in the lung tissue was changed during smoke ventilation in both rat and hamster. The amount of radioactivity in some lipid fractions was increased by cigarette smoke, the increase being greatest in triacylglycerols. This study shows that pulmonary metabolism of AA is changed by cigarette smoke ventilation but not by pre-exposure of animals. Both incorporation of AA into lung lipids and efflux of metabolites from the lungs are affected by cigarette smoke.