PEPTIDOLEUKOTRIENE (PLT) RELEASE FROM GUINEA-PIG LUNG MAST-CELLS

Guinea pig lung mast cells can be isolated and purified to high purity. This has given us the opportunity to study in greater detail mediator release from these cells. Both immunologic (ovalbumin sensitized) and nonimmunologic (calcium ionophore, CaI) stimuli caused a dose-dependent release of histamine and pLT from monodispersed lung cells and highly purified lung mast cells. Examination of the time release curve for pLT revealed a 5-min lag in the release of this mediator and a peak release at 60 min after challenge with antigen. Verification of pLT release was obtained by use of the 5-lipoxygenase inhibitor A64077 (Zileuton). Pretreatment of lung mast cells with the 5-lipoxygenase inhibitor prevented release of pLT by either antigen or CaI but had no appreciable effect on histamine release (HR). The pulmonary mast cell appears to be an important contributor to pLT release in the guinea pig lung.