Human white blood cells, particularly neutrophils and macrophages produce several biologically active molecules including oxygen-derived free radicals and some metabolites of arachidonic acid which are involved in mechanisms of host defence. White blood cells of the blue-tongue lizard Tiliqua scincoides produce certain derivatives of arachidonic acid which include prostaglandins, thromboxane and 12- and 15-hydroxyeicosatetraenoic acid. The ability to produce these compounds indicates that these animals possess the enzymes cyclooxygenase, 12- and 15-lipoxygenase, T. scincoides white blood cells did not produce leukotriene B4 or 5-hydroxyeicosatetraenoic acid indicating that, unlike human white blood cells, they do not possess a 5-lipoxygenase enxyme. T. scincoides cells are also capable of producing the oxygen-derived free radical superoxide enzyme.
