The differential role of exogenous and endogenous prostacyclin in the control of renin release from dog renal cortical slices

Using a continuous superfusion system of dog renal cortical slices, we studied the role of prostacyclin in the control of renin release. Superfusate renin activity and prostacyclin as 6-keto-prostaglandin F1alpha, a stable metabolite of prostacyclin, concentrations were measured by radioimmunoassay. Exogenous prostacyclin (0.1, 1, 10 microM) produced a concentration dependent and significant increase in renin release. The calcium ionophore A23187 (10 microM) produced a significant increase in 6-keto-prostaglandin F1alpha release and a significant decrease in renin release. A23187 (10 microM) hardly produced changes of 6-keto-prostaglandin F1alpha release and renin release in the absence of Ca2+. Pretreatment with indomethacin (10 microM) completely abolished the stimulatory effect of A23187 (10 microM) on 6-keto-prostaglandin F1alpha release. On the other hand, the inhibitory effect of A23187 on renin release in the pretreatment with indomethacin was almost equal to that in the "untreatment" with indomethacin. Moreover, we found that there was no association of 6-keto-prostaglandin F1alpha liberation and renin activity. These results indicate that exogenous prostacyclin promotes renin release, and suggest that renin release is not to be modulated by A23187-induced prostacyclin synthesis in dog renal cortical slices.