Effects of prostacyclin and prostaglandin E 1 on cyclic AMP metabolism and calcium efflux in isolated renal cortical tubules

Abstract

Comparative effects of prostaglandin E 1 (PGE 2 1) and prostacyclin (PGI 2) on cyclic AMP (cAMP) metabolism and efflux of 45Ca in isolated renal cortical tubules from hamsters were investigated. Both (PGE 2 1) and renal cortical tubules from hamsters were investigated. Both PGE 2 1 and PGI 2 increased tissue concentrations and production of cAMP in isolated tubules with effects of (PGE 2 1) being slightly greater than those o PGI 2. Both prostaglandins produced dose-related increases in cAMP production over identical concentration ranges (0.01–15 μg/ml). Degradation of cAMP, estimated as the difference in tissue levels of cAMP in the presence and absence of maximal amounts of the phosphodiesterase inhibitor, 1-methyl-3-isobutylxanthine (MIX), increased following addition of either prostaglandin with increases paralleling increases in cAMP production. Simultaneous addition of maximal amounts of both prostaglandins resulted in a combined effect on cAMP production which was nonadditive. Both prostaglandins produced dose-related increases in efflux of 45Ca from Both prostaglandins produced dose-related increases in efflux of 4Ca frolated tubules. Changes in 45Ca efflux were closely related to changes in cAMP levels produced by either prostaglandin. Simultaneous addition of chaimal concentrations of (PGE 2 1) and PGI 2 produced changes in addition of maximal concentrations of PGE 2 1 and PGI 2 produced changes in 45Ca efflux which were nonadditive. The results indicate that both prostaglandins increase cAMP production and efflux of calcium in isolated renal prostaglandins increase cAMP production and efflux of calcium in isolated renal coritical tubules and may share a common target cell type in these responses.