MAMMALIAN LIPOXYGENASES - ARE THEY ONLY INVOLVED IN THE ARACHIDONIC-ACID CASCADE

9-HODE is reported to be formed either by the prostaglandin H synthase or by certain lipoxygenases. In some inflammatory diseases (psoriasis, Mediterranian fever) elevated concentrations of 9-HODE are found in plasma. Therefore its possible role as a proinflammatory mediator requires special attention. The clear evidence that erythroid 15-lipoxygenase directly oxygenates membranes implies that also other 15-lipoxygenases such as those of macrophages, eosinophils and of endothelial cells may exert this activity. Oxygenation of membrane lipids changes the fluidity of the membrane and may therefore affect calcium permeability and the responsiveness of receptors. © 1991 Birkhäuser Verlag.