EFFECTS OF FE2+, ZN2+, CU2+ AND SE4+ ON THE SYNTHESIS AND CATABOLISM OF PROSTAGLANDINS IN RABBIT GASTRIC ANTRAL MUCOSA

Effects of Fe2+, Zn2+, Cu2+ and Se4+ on the synthesis and catabolism o f prostaglandins (PGs) in rabbit gastric antral mucosa were examined. Fe2+ inhibited the cyclooxygenase activity in the microsomal fraction. Zn2+ suppressed the endoperoxide E(2) isomerase activity in the micro somal fraction and the 15-hydroxy PG dehydrogenase (PGDH) activity in the cytosolic fraction. Cu2+ stimulated the cyclooxygenase activity, i nhibited the PGDH activity and possibly induced non-enzymatic reductio n of PGG(2) or PGH(2) to PGF(2 alpha). Se4+ possibly induced the non-e nzymatic reduction of PGG(2) or PGH(2) to PGF(2 alpha), as well as Cu2 +. These results suggest that Fe2+, Zn2+, Cu2+ and Se4+ can be modulat ors of the gastric antral mucosal PG levels by affecting the PG synthe sizing enzymes, PG catabolizing enzyme and/or non-enzymatic reduction of PGG or PGH to PGF.