Synthesis of diene prostaglandins in freshwater fish

Biosynthesis of PGD2, PGE2 and PGF2 alpha in four species of freshwater fish, Tilapia mossambica, Cyprinus carpio, Heteropneustes fossilis and Clarius batrachus was studied. Both arachidonic acid and PGH2 were used as substrates. When PGH2 replaced arachidonic acid in the enzymic reaction, there was a 3- to 4-fold increase in PGE2 synthesis, but no such increase in the synthesis of PGF2 alpha and PGD2 was observed.