Regional distribution of lipoxygenase activities in porcine ciliary epithelium

Nonpigmented epithelial (NPE) cells and pigmented epithelial (PE) cells were separated from porcine ciliary processes without protease treatment. The relative capabilities of NPE cells and PE cells to synthesize 5-hydroxyeicosatetraenoic acid (5-HETE), 12-HETE, and 5,12-diHETE from 1-[14C] arachidonic acid were determined. HETE compounds were separated by HPLC. The capability of NPE cells to synthesize 5-lipoxygenase and 12-lipoxygenase products was, respectively, five-fold and 2.5 fold higher than that of PE cells. The formation of 5-HETE, 12-HETE and 5,12-diHETE was inhibited virtually completely by 50 microM nordihydroguaiaretic acid but not by 5 microM indomethacin. The major product formed both by NPE cells and PE cells was 12-HETE.