Figure 4.

Reversal of the inhibitory effect of pyrrophenone on thapsigargin-induced LT biosynthesis. PMN suspensions (37°C, 5 × 10⁶ cells ml⁻¹) were stimulated with 100 nM thapsigargin for 10 min as described in Methods. AA was added simultaneously with thapsigargin. ADA (0.3 U ml⁻¹) and 100 nM pyrrophenone were added 10 min before the stimulation of the cells with thapsigargin. Incubations were stopped by the addition of 0.5 volume of a cold (4°C) stop solution (MeOH/MeCN, 1/1) containing 12.5 ng of both 19-OH-PGB₂ and PGB₂ as internal standards and 5-LO products were analyzed as described in Methods. Data represent the mean (± s.e.m.) of three separate experiments, each performed in duplicate.