LTB4 inhibits adenylyl cyclase activities in CHO-LTBR cells (mean +/- s.e., n = 3)

LTB4 inhibited 0.5 mM forskolin-induced adenylyl cyclase activities (closed columns). This inhibition was abolished by pretreatment of the cells with 100 ng/ml PTX for 12 h (open columns). The forskolin-induced cAMP levels in the absence of LTB4 were 983+/-148 pmol/10e6 in untreated cells and 472+/-36 pmol/10e6 in PTX-treated cells. Statistically significant differences between control cells treated with forskolin alone, and cells treated both with forskolin and LTB4 are indicated (* p < 0.05, ** p < 0.01, unpaired t-test).