COMPARISON OF THE EFFECTS OF PROSTAGLANDIN-I2 AND PROSTAGLANDIN-E2 STIMULATION OF THE RAT-KIDNEY ADENYLATE CYCLASE-CYCLIC AMP SYSTEMS

Prostacyclin (Prostaglandin I2) effects on the rat kidney adenylate cyclase-cyclic AMP system were examined. Prostaglandin I2 and prostaglandin E2, from 8 · 10-4 to 8 · -7 M stimulated adenylate cyclase to a similar extent in cortex and outer medulla. In inner medulla, prostaglandin I2 was more effective than prostaglandin E2 at all concentrations tested. Both prostaglandin I2 and prostaglandin E2 were additive with antidiuretic hormone in outer and inner medulla. Prostaglandin I2 and prostaglandin E2 were not additive in any area of the kidney, indicating both were working by similar mechanisms. Prostaglandin I2 stimulation of adenylate cyclase correlated with its ability to increase renal slice cyclic AMP content. Prostaglandin I2 and prostaglandin E2 (1.5 · 10-4 M) elevated cyclic AMP content in cortex and outer medulla slices. In inner medulla, with Santoquin® (0.1 mM) present to suppress endogenous prostaglandin synthesis, prostaglandin I2 and prostaglandin E2 increased cyclic AMP content. 6-Ketoprostaglandin F1α, the stable metabolite of prostaglandin I2, did not increase adenylate cyclase activity or tissue cyclic AMP content. Thus, prostaglandin I2 activates renal adenylate cyclase. This suggests that the physiological actions of prostaglandin I2 may be mediated through the adenylate cyclase-cyclic AMP system. © 1979.