This study was performed to determine the involvement of type II phospholipase A 2 (PLA 2 -II) in renal injury caused by ischemia and reperfusion. Ischemia and reperfusion significantly elevated levels of blood urea nitrogen and serum creatinine in rats. These increases were significantly reduced by i.v. administration of rabbit IgG F(ab')2 fragments against rat PLA 2 -II. Increased levels of acid-stable PLA 2 activity in the kidney were caused by ischemia and reperfusion, and were suppressed by administration of anti-PLA 2 -II F(ab')2. Increased levels of myeloperoxidase activity, a marker of neutrophil infiltration, in the kidney were also reduced after anti-PLA 2 -II F(ab')2 treatment. These results suggest that PLA 2 -II plays a pivotal role in pathogenesis of ischemia and reperfusion injury through induction of neutrophil infiltration.