Actions and interactions of lipoxygenase and cyclo-oxygenase products in respiratory and vascular tissues.

Actions of leukotrienes (LTs) B4, C4, D4 and E4 were found to be largely mediated via formation of cyclo-oxygenase products in guinea-pig isolated perfused lung and parenchymal strips. In contrast, LTs exerted a direct contractile effect on human isolated parenchymal and bronchial strips. An LT-like substance which had similar biological actions to LTD4 was generated from porcine and guinea-pig vascular tissue. The highest concentration of this material was formed by coronary and pulmonary arteries and the surrounding adventitia, as well as from the lung parenchyma.