Fig. 1
Model of the metabolization of arachidonic acid (AA). AA is metabolized by 3 different groups of enzymes: cyclooxygenases (COX), lipoxygenases (LOX) and epoxygenases (cytochrome P450). The COX pathway consists of 2 isozymes: COX-1 and COX-2. Both isozymes metabolize AA into PGG2 and then into PGH2, which is further converted to the prostaglandins (PGs) PGD2, PGE2, PGF2α, PGI2 and thromboxane A2, (TXA2) by their respective synthases [3]. Each product binds to its specific membrane receptor. The CYP-450 pathway converts AA by epoxygenases and ω-hydroxylase into other downstream products, not shown. The LOX pathway consists of 3 main enzymes termed 5-LOX, 12-LOX and 15-LOX (isozymes 15-LOX-1 and 15-LOX-2). They metabolize AA into hydroperoxyl-eicosatetraenoic acids (HPETEs), which are further reduced to hydroxyeicosatetraenoic acids (HETEs). The 5-LOX enzyme differs by also metabolizing 5-HPETE into leukotriene A4 by means of 5-lipoxygenase-activating protein (FLAP). *Enzymes already investigated in our laboratory; data published. Receptors/enzymes investigated in this study are underlined with red