LIPOXYGENASES IN CORNEAL EPITHELIA OF MAN AND CYNOMOLGUS MONKEY

Human and monkey corneal epithelia were investigated for lipoxygenases . The low-speed supernatant of human corneal epithelium converted arac hidonic acid to one prominent metabolite, which was identified as 15-h ydroxyeicosatetraenoic acid by gas chromarography mass spectrometry an d by ultra violet analyses. Eicosatetraynoic acid, a lipoxygenase inhi bitor, reduced the formation of 15-hydroxyeicosatetraenoic acid, by 90 % at 30 mu M, while esculetin (30 mu M) and diclofenac (100 mu M) did not inhibit the biosynthesis. Immunohistochemical analysis of human co rnea using a polyclonal antibody against recombinant human reticulocyt e 15-lipoxygenase showed staining of the epithelium, but not the strom a. The cytosolic fraction of epithelial cells of the monkey, Macaca fa scicularis, converted [1-C-14]arachidonic acid to two major metabolite s, which were identified as 15S-hydroxyeicosatetraenoic and 12S-hydrox yeicosatetraenoic acids by cochromatography with these compounds on re verse-phase, straight-phase and chiral high-performance liquid chromat ography. Lipoxygenase activity could not be detected in the microsomal fraction. The results provide biochemical, pharmacological and immuno histological evidence of a 15-lipoxygenase in human corneal epithelium and suggest that monkey corneal epithelium contains cytosolic 12- and 15-lipoxygenases.