Cyclooxygenase-catalyzed formation of 9-hydroxylinoleic acid by guinea pig alveolar macrophages under non-stimulated conditions.

Data are presented on the formation of a linoleic acid oxygenation product under basal conditions by guinea pig alveolar macrophages (AM). Under non-stimulated conditions 20 X 10(6) AM released about 1 nmol 9-hydroxylinoleic acid (9-HODE) during a 15 min incubation. Furthermore, AM released more than 2 nmol 12-hydroxy-5,8,10-heptadecatrienoic acid (HHT), a byproduct of the formation of thromboxane A2. 9-HODE and HHT were the most prominent products formed under the incubation conditions used. These products were formed via a cyclooxygenase-catalyzed reaction, since their formation was inhibited by 1 microM indomethacin. Thus, under basal conditions AM possess substantial cyclooxygenase activity. The biological significance of 9-HODE and related substances is discussed.