Effect of alpha-adrenergic stimulation on prostacyclin and renin release in the rat kidney

The relationship between renin secretion and PGI2 production, in response to intrarenal infusion of norepinephrine, was examined in the isolated perfused rat kidney. Infusion of norepinephrine in a dose which caused substantial vasoconstriction (100 ng/min), markedly increased urinary excretion of 6-keto PGF1 alpha, the stable derivative of PGI2, without significantly altering renin secretion measured in the effluent perfusate. No change in urinary 6-keto PGF1 alpha occurred when vasoconstriction was prevented by infusing the alpha-adrenoceptor blocking drug phenoxybenzamine (2 x 10(3) ng/min) alongside norepinephrine (100 ng/min). However, under these conditions there was marked stimulation of renin secretion which, as has been demonstrated previously, is mediated by a beta-adrenoceptor. There were significant increases in urine flow rates during both vasoconstrictor and non-vasoconstrictor infusions. These findings clearly indicate that in the rat kidney prostacyclin production and renin release in response to norepinephrine are dissociated.