We tested the effect of prostaglandins PGF2 alpha and PGE1 on the transport of 36Cl and 22Na by canine tracheal epithelium. Sheets of epithelium were mounted in Ussing chambers and short-circuited. Addition of PGF2 alpha to the mucosal side resulted in an increase of net Cl secretion from 0.71 +/- 0.41 to 2.40 +/- 0.67 mu eq . cm-2 . h-1 without significant effect on net Na absorption. Prostaglandin E1 on the mucosal side increased net Cl secretion from 1.36 +/- 0.31 to 2.69 +/- 0.35 and decreased Na absorption from 0.87 +/- 0.16 to 0.49 +/- 0.09. Indomethacin significantly depressed net Cl secretion from 1.36 +/- 0.36 to 0.57 +/- 0.22. Subsequent addition of PGE1 augmented net Cl secretion to 3.88 +/- 0.75. PGE1 did not enhance [14C]mannitol fluxes across this epithelium. Cellular levels of cAMP increased in response to PGE1 from 130 +/- 12.7 to 642 +/- 33.4 pmol . mg prot-1 . 10 min-1, whereas PGF2 alpha had no effect. These data suggest that although effects of PGF2 alpha and PGE1 are similar as pertains to net Cl secretion, they differ in their effects on Na transport and their capacity to increase cAMP levels. Alterations in Cl and Na transport in response to PGE1 are likely to be mediated, at least in part, by the adenylate cyclase-cAMP system. Furthermore, endogenous prostaglandins may have an important regulatory role in ion transport by airways epithelium.