Inhibition of Prostaglandin-Induced Pulmonary Vasoconstriction by Organic Acid Transport Inhibitors 1

Abstract

Summary

Probenecid and bromcresol green (BGr), reported to be PG transport inhibitors, were tested for their effectiveness in modifying the vasopressor responses of arachidonic acid (AA), an endoperoxide analogue, PGF_2α, and norepinephrine in the isolated perfused canine lung lobe. Only the pulmonary pressor action of AA was blocked by pretreatment with indomethacin. Probenecid attenuated AA responses and blocked those of PGF_2α, in a dose-related manner. BGr had no antagonistic activity against AA and inhibited PGF_2α action by 50%. Probenecid and BGr appear to inhibit PGF_2α, differently. Neither blocked the pressor action of the endoperoxide analogue, and neither attenuated the norepinephrine pressor action at PG inhibiting concentrations. The use of organic acid transport inhibitors represents a potentially useful approach in studying the mechanisms of action of AA and its metabolic products.