Effect of transmethylation-reaction and increased levels of cAMP on superoxide generation of guinea-pig macrophages induced with wheat germ agglutinin and phorbor myristate.

Superoxide (O2-) generation of guinea-pig macrophages induced by wheat germ agglutinin (WGA) was suppressed to a great extent by the inhibition of transmethylation with 3'-deazaadenosine. When macrophages were stimulated with phorbor myristate (PMA) instead of WGA, the suppression of O2- generation of macrophages was observed to be slight despite the presence of 3'-deazaadenosine. These results were confirmed under various conditions. Thus the WGA-stimulated O2- generation of macrophages is probably associated with transmethylation, but the PMA-stimulated O2- generation is not. WGA-stimulated O2- generation of macrophages was also inhibited in the presence of dibutyryl cAMP or prostaglandin E2 (PGE2), substances that increase intracellular cAMP, but PMA-stimulated O2- generation was only slightly affected by these compounds. These results suggest that the mechanism for O2- generation of macrophages caused by WGA is different from that for O2- generation caused by PMA.