We previously discovered that Caenorhabditis elegans synthesizes Cox-independent F-series prostaglandins (PGs). To delineate the Cox-independent prostaglandin pathways and evaluate their role in sperm motility in C. elegans, we developed a novel biochemical method for the rapid production of F-series PGs using arachidonic acid as the substrate and worm lysate as source of enzyme(s). Among the four F2-series PGs produced in the reaction, three of them were identified as 8-isoPGF2 alpha, 5iPF2VI, and PGF2 alpha based on their retention times and MS/MS spectral comparison with standards using LC-MS/MS. PG production was not markedly affected by specific antioxidants, or Cox, Lox, and Cyp inhibitors, suggesting that these PGs are formed through a novel, biologically regulated mechanism in C. elegans. This study also assessed the ability of 8-isoPGF2 alpha, 5iPF2VI, PGF2 alpha, and a mixture containing these PGs in a 0.5/0.08/1 ratio that reflects their synthetic composition to modulate sperm motility in fat-2 mutants. PGF2 alpha and the PG mixture at 25 mu M concentration significantly stimulated sperm velocity by 28% and 38%, whereas 8-isoPGF2 alpha and 5iPF2VI reduced the velocity by 21% and 30%, respectively, compared to vehicle control. These results indicate that the sperm motility effects of PGs are structure-and composition-dependent in C. elegans.
