Figure 3.

Effects of selective prostaglandin EP receptor agonists on cyclic AMP generation by guinea-pig tracheal epithelial cells. Cells were pre-incubated for 15 min with rolipram (10 μM) and thereafter incubated with increasing concentrations of PGE₂ (open circles), 16,16-dimethyl PGE₂ (solid triangles), 11-deoxy PGE₂ (solid diamonds) or butaprost (open squares). The conversion of [³H]-ATP to [³H]-cyclic AMP was assayed as described in Methods. The points are the mean±s.e.mean of 4–8 determinations made with separate cell preparations.