Effect of 5-LOX and COX-2 inhibitors on eicosanoid formation in human leukocytes. HKE2 (A) and HKD2 (B) as well as 5-HETE (C), LTB4 (D), and PGE2 (E) were quantified by using LC-SRM-MS analyses after derivatization with AMPP. Inhibitors were added 15 min before stimulation with LPS (10 μg/ml) and A23187 (5 μM) at 37°C for 15 min. The inhibitors used were NS398 (1 μM), AA861 (10 μM), or MK886 (5 μM). The box plots indicate the spread of the values between the 25th and 75th percentiles. Solid horizontal line: median; dashed horizontal line: the mean; filled circles: the highest and lowest data points. Leukocytes from 7 volunteers were used. Veh, vehicle. *P < 0.05; **P < 0.01; ***P < 0.001 in comparison to stimulated and vehicle-treated sample.