Synthesis of slow reacting substance-like activity in rabbit conjunctiva and anterior uvea.

The ability of rabbit conjunctiva and anterior uvea to synthesize lipoxygenase products was assessed. Using autoradiographic techniques, we demonstrate that rabbit anterior uvea synthesizes 5 and 12 lipoxygenase products such as 12-HETE, 5-HETE and 5,12-DiHETE and cyclooxygenase product HHT from 14C-arachidonic acid. Indomethacin pretreated conjunctiva and anterior uvea generated slow reacting substance (SRS)-like activity from arachidonic acid in the presence of reduced glutathione and A23187. This SRS-like activity contracted guinea pig ileum. Specific SRS-like activity antagonist FPL-55712 inhibited the contractions of guinea pig ileum induced by SRS-like substance generated by either conjunctiva or anterior uvea. The activity was still present in the sample following extraction with organic solvents. SRS-like activity was destroyed by arylsulfatase and its generation was prevented by either boiling or pretreatment with cyclooxygenase/lipoxygenase inhibitors, BW755 and nordihydroguaiacetic acid. These results indicate that following cyclooxygenase inhibition by indomethacin rabbit conjunctiva and anterior uvea generate SRS-like activity from arachidonic acid via lipoxygenase pathways.