Prostaglandin synthesis and accumulation by porcine ciliary epithelium

The activity to synthesize prostaglandins (PGs*) from arachidonic acid [i.e. cyclooxygenase (CO) activity] was compared between nonpigmented epithelial (NPE) cells and pigmented epithelial (PE) cells from porcine ciliary processes. PG synthesizing activities were about the same (0.58 and 0.52 pmol per mg protein per 15 min for NPE and PE, respectively), and inhibited by indomethacin and anti-CO antibody but not by nordihydroguaiaretic acid. By immunogold labeling, CO immunoreactivity was found both in NPE and PE. The present results and the previous observation on higher PG omega/omega-1 hydroxylation activities in NPE than in PE, taken together, suggest that controlled synthesis and inactivation of PGs may have a role in functions of NPE. When PGE2 was incubated with NPE or PE, NPE cells accumulated PGE2 more actively than did PE cells. PG uptake by the NPE cells may prevent aqueous and vitreous PGs from entering the anterior chamber and causing anterior uveitis.