Histamine release from serosal mast cells by intermediate products of arachidonic acid metabolism

In the present paper we report the results of experiments carried out to measure the release of histamine from isolated rat mast cells during the metabolic activation of arachidonic acid. Arachidonic acid (10^–8–10^–4M) and the terminal products (10^–6M) of the arachidonic acid pathways were devoid of any significant histamine releasing properties. A substantial amount of histamine was released from rat mast cells by low concentrations of arachidonic acid during incubation with prostanoid generating systems, such as guinea-pig lung microsomes, rat serosal macrophages and polymorphonuclear cells and prostaglandin-H-synthase from calf seminal vesicles. The release of histamine was not accompanied by a leakage of lactate dehydrogenase and was blocked byd-mannitol and by lipoxygenase and cyclo-oxygenase pathway inhibitors. The data are consistent with the hypothesis that free radical derivatives of arachidonic acid, originating from hydroperoxy fatty acids, are generated during catalysis, causing mast cell histamine release.