Evidence for functionally distinct pools of phospholipase responsible for prostaglandin release from the perfused guinea-pig lung.

The release of prostaglandin- and thromboxane-like material from the isolated perfused guinea-pig lung was elicited by challenge with arachidonic acid, bradykinin, histamine and ovalbumin (in ovalbumin-sensitised animals), and detected by superfusion cascade bioassay. Mepacrine inhibited release to all agents except arachidonic acid. Dexamethasone and fludrocortisone inhibited release induced by histamine and anaphylactic challenge but not by bradykinin or arachidonic acid. These results suggest two functionally distinct pools of phospholipase responsible for initiating prostaglandin biosynthesis in the guinea-pig lung.