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 F 1 α , a stable metabolite of prostacyclin, concentrations were measured by radioimmunoassay. Exogenous prostacyclin (0.1, 1, 10 μM) produced a concentration dependent and significant increase in renin release. The calcium ionophore A23187 (10 μM) produced a significant increase in 6-keto-prostaglandin F 1 α release and a significant decrease in renin release. A23187 (10 μM) hardly produced changes of 6-keto-prostaglandin F 1 α release and renin release in the absence of Ca 2 + . Pretreatment with indomethacin (10 μM) completely abolished the stimulatory effect of A23187 (10 μM) on 6-keto-prostaglandin F 1 α 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 F 1 α 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.