INHIBITION OF ARACHIDONIC-ACID RELEASE BY NORDIHYDROGUAIARETIC ACID AND ITS ANTIOXIDANT ACTION IN RAT ALVEOLAR MACROPHAGES AND CHINESE HAMSTER LUNG FIBROBLASTS

The ability of nordihydroguaiaretic acid (NDGA) to inhibit arachidonic acid (AA) release from rat alveolar macrophages treated with t-butyl hydroperoxide (tBOOH) or from Chinese hamster lung fibroblasts (V79 cells) treated with linoleic acid hydroperoxide (LOOH) was examined. Treatment of alveolar macrophages with 100 μm tBOOH significantly increased arachidonic acid release and its conversion to metabolites. Pretreatment of macrophages with NDGA (≥2.5 μm) inhibited the release of AA and its subsequent metabolism following addition of tBOOH. Treatment of V79 cells with 1 μm LOOH stimulated the release of AA. Pretreatment with either 1 or 10 μm NDGA prior to the addition of LOOH inhibited the release of AA. A23187 (2 μm)-stimulated release of AA from V79 cells was less sensitive to NDGA inhibition. Pretreatment with 10 μm NDGA, but not with 1 μm NDGA, inhibited A23187-stimulated release of AA. PLA2-dependent hydrolysis of micelle preparations of disaturated phosphatidylcholine was not inhibited by NDGA. Previous studies have suggested that the addition of peroxides alters cells by inducing lipid peroxidation so that the action of phospholipases upon their membranes is enhanced. The results suggest that NDGA, a lipid-soluble antioxidant which traps free radicals, indirectly blocked the action of phospholipases upon cell membranes by inhibiting lipid peroxidation. © 1990.