Effect of stimulated neutrophils on cyclic nucleotide content in isolated rat glomeruli

In this study we examined the effect of cell-free supernatants from stimulated neutrophils on the adenosine 3',5'-cyclic monophosphate (cAMP) and guanosine 3',5'-cyclic monophosphate (cGMP) content in isolated rat glomeruli. Cell-free supernatants obtained from unstimulated and stimulated (with opsonized zymosan for 30 min at 37 degrees C) cells were incubated for 5 min with glomeruli and tubules. Cell-free supernatants from stimulated neutrophils significantly increased the cAMP content in the glomeruli from 34.7 +/- 2.3 to 99.7 +/- 7.0 pmol/mg protein (n = 23; P less than 0.001). The cAMP content in the tubules and the cGMP content in the glomeruli or tubules was not altered by the cell-free supernatants from stimulated neutrophils. The cAMP response of the glomeruli was not modified when supernatants were obtained from neutrophils stimulated in the presence of superoxide dismutase, a scavenger of superoxide anion. In contrast, the glomerular response to supernatants obtained from neutrophils stimulated in the presence of catalase, a scavenger of hydrogen peroxide, or in the presence of methionine or taurine, scavengers of hypochlorous acid, was significantly reduced (P less than 0.001). Additional experiments that used prostaglandin synthesis inhibitors (meclofenamate and ibuprofen) and phospholipase inhibitor (quinacrine) suggested that the reactive oxygen metabolites increase the cAMP content in glomeruli by stimulating phospholipase activity and thus enhancing prostaglandin synthesis. These data show that reactive oxygen metabolites generated by stimulated neutrophils increase cAMP content in glomeruli and suggest that neutrophils may modulate the glomerular function and the inflammatory response in glomerular disease by altering the cAMP content.