LEUKOTRIENE C-4 BIOSYNTHESIS IN ISOLATED AUGUST RAT PERITONEAL LEUKOCYTES

THE mixed leukocyte population obtained from the peritoneum of the Aug ust rat is a potentially important experimental model of inherent eosi nophilia that has not been well characterized Zn the present study, is olated cell preparations generated a concentration-dependent release o f leukotriene (LT) C-4 when exposed to the Ca2+ ionophore A23187, reac hing maximal stimulation at 5.0 mu M. This response was inhibited by t he 5-lipoxygenase activating protein antagonist MK-886 (0.1 mu M), nom inally Ca2+ and Mg2+-free incubation media and by activation of protei n kinase C via phorbol 12-myristate 13-acetate (50 nM). These findings establish a model system for investigating LTC(4) profiles contingent with innate peritoneal eosinophilia and are consistent with the hypot hesis that cellular LTC(4) biosynthesis is phosphoregulated.