Release of prostaglandin E2 and thromboxane B2 by mixed isolated human lung cells

Human lung specimens were minced and treated for 30 min with collagenase (1 mg ml-1) and DNase (0.1 mg ml-1) to obtain a suspension of viable (approximately 80%) and metabolically active lung cells (5 x 10(6) cells per gram of tissue). Treatment of these mixed lung cells with bradykinin (1.25 x 10(-6) to 1 x 10(-5) M) and f-Met-Leu-Phe (f-MLP; 1 x 10(-8) to 5 x 10(-6) M) did not stimulate to a substantial extent the release of prostaglandins and thromboxanes (measured with novel Enzyme Immunoassays). The only concentration of PAF that stimulated significantly the release of icosanoids from lung cells was 5 x 10(-7) M. Phorbol myristate (PMA; 5 x 10(-8) to 2 x 10(-6) M) and ionophore a-21387 (2.5 x 10(-6) to 2 x 10(-5) M) strongly stimulated the release of prostaglandins and thromboxanes by dispersed human lung cells. These findings support previous observations showing that human lungs have the enzymes necessary for the synthesis and release of prostaglandins and thromboxanes but stimulation of the release of these mediators is not obtained with the hormonal stimuli that are active in guinea pigs. Studies in progress will purify the cell populations and characterize the cells responsible for the release of these icosanoids.