Abstract Various drugs have been shown to stimulate surfactant phospholipid metabolism. Particularly β-adrenergic agonists play an important role under physiologic conditions. For the first time we have studied whether nitrogen dioxide (NO 2) inhalation alters β-adrenergic regulation of surfactant phospholipid metabolism in the model of the isolated lung. Rats were continuously exposed in vivo to a 5 ppm NO 2-containing atmosphere for 48 hr. The lungs were isolated and perfused in presence of the β-adrenergic agonist dopexamine and surfactant metabolism was studied in three lung compartments: (1) lung lavage, (2) lung tissue, and (3) lavagable free alveolar cells. We found that (1) in normal rat lungs dopexamine increased the incorporation of palmitate and choline from the perfusate into lung lavage phospholipids. In nitrogen dioxide exposed rat lungs β-adrenergic stimulation did not cause an increase in precursor incorporation. No significant difference in unstimulated precursor incorporation was found for normal and NO 2-exposed rat lungs. (2) Lung tissue from rats exposed to NO 2 showed a decreased precursor incorporation into disaturated phosphatidylcholine due to an augmented cellular pool size. (3) Lavagable alveolar cells showed an increased palmitate uptake after nitrogen dioxide inhalation and by β-adrenergic stimulation. From these data we conclude that nitrogen dioxide inhalation impairs the β-adrenergic regulation of surfactant phospholipid metabolism. Moreover these data underline the importance of β-adrenergic agonists in surfactant metabolism.