Selective increase in phospho-p38 mitogen-activated protein (MAP) kinase expression in lysates of endothelial cells treated with (A) 17,18-epoxy-EPA (10 µM), but not (B) 8,9- or 11,12-epoxy-EPA (10 µM). Phosphorylated/total MAP kinase ratios were determined relative to control (dimethyl sulphoxide-treated) cells. Densitometric analyses of representative experiments from three separate experiments are shown: open columns, 30 min; solid columns, 60 min; and hatched columns, 90 min of treatment.