Effects of Prostaglandins on Superoxide Production by Human Polymorphonuclear Leukocytes

The effects of prostaglandin analogues (PGE1, E2, D2, I2) on superoxide (O-2) production by human polymorphonuclear leukocytes (PMN) stimulated by the supernatant of a B. gingivalis 381 sonicate (BGsup) were studied in vitro by a cytochrome C reduction method. O-2 production by the PMN was enhanced distinctly by the BG-sup and this increased O-2 production was nullified by the addition of PGE1, E2, or D2 at a concentration of 0.02ug/ml. However, PGI2, even at a concentration of 2ug/ml, could not bring down the O-2 production. The amount of intracellular cyclic AMP (cAMP) of PMN treated with these PG were measured; and the results indicated all of these PG caused on elevation of the cAMP level. The effect of dibutyryl cAMP, an analogue of cAMP, on O-2 production was also examined, and almost the same results were obtained as with the PG. These results suggest that the reduction in B. gingivalis-induced O-2 production by PMN that occurred by addition of PG was due to the increase in intracellular cAMP; that is, cAMP appears to suppress the O-2 production augmented by the BG-sup.