Inhibition of renin release from rat kidney slices by the angiotensins

The mechanism and structural basis of the inhibition of renin release by angiotensin II (AII) were studied in rat kidney slices. Renin release was inhibited by AII and the (2-8), (3-8), (4-8), and (5-8) peptides of AII (5 X 10(-5) M). These constituent peptides of AII which share a common carboxyl terminus inhibited renin release with a sharp decrease in potency when the amino-terminal amino acid was removed. Saralasin attenuated the inhibition of renin release induced by equimolar concentrations of AII. Dose-response curves for AII and the (2-8) peptide [angiotensin III (AIII)] indicate that AII is a more potent inhibitor of renin release than is AIII. Depletion of renal norepinephrine by reserpine (10 mg/kg, i.p.) or pretreatment of slices with papaverine (1 X 10(-4) M) did not block the action of AII. The data give evidence for a direct action of AII on the juxtaglomerular cells independent of an interaction with either the sympathetic nervous system or the arteriolar baroreceptor and suggest that the intrarenal receptors that mediate AII-induced inhibition of renin release differ from AII receptors in the adrenal cortex.