SUMMARY
Polymorphonuclear neutrophils (pmn) from 4 ovariectomized healthy cows were incubated with 0 (control), 10-8, 10-7, and 10-6M arachidonic acid metabolites of the cyclo- and lipoxygenase pathways for 30 minutes, and with steroids for 2 hours. Immediately after incubation, pmn were subjected to the following function assays: chemotaxis against zymosan-activated serum, chemotaxis against arachidonic acid metabolite or steroid at the doses given (only control pmn were tested), random migration, ingestion of 125I-iododeoxyuridine-labeled Staphylococcus aureus (125I-IdUR-S aureus), iodination of proteins, cytochrome C reduction, antibody-independent and -dependent cell-mediated cytotoxicity (aicc and adcc). Prostaglandin F2α was chemoattractant and stimulated ingestion of 125I-IdUR-S aureus. Prostaglandin E2 stimulated cytochrome C reduction, whereas prostacyclin inhibited iodination of proteins. Thromboxane B2 stimulated adcc. Leukotriene B4 was chemoattractant for bovine pmn and stimulated random migration and aicc. 5-Hydroxyeicosatetraenoic acid was also chemoattractant, but inhibited ingestion of 125I-IdUR-S aureus. 15-Hydroxyeicosatetraenoic acid was chemoattractant and decreased adcc. Lipoxin A4 stimulated random migration, whereas lipoxin B4 inhibited chemotaxis against zymosan-activated serum, but was chemoattractant and stimulated cytochrome C reduction. 12-Hydroxyhepadecatrienoic acid and 12-hydroxyeicosatetraenoic acid did not influence any of the pmn functions tested. Of the steroids tested, cortisol increased adcc, and progesterone stimulated cytochrome C reduction, but decreased adcc. 17β-Estradiol and estrone were chemoattractant and stimulated cytochrome C reduction. In addition, estrone also stimulated random migration. Those results suggest that eicosanoids and steroids directly influence function of bovine pmn in vitro in a stimulatory or inhibitory manner, or both, and may act as modulators of bovine pmn function in vivo.