Inhibition of renin secretion in the isolated rat kidney by angiotensin I.

The effect of angiotensin I on renal perfusion pressure, and on basal and isoprenaline stimulated renin secretion, was examined in the isolated perfused rat kidney. The increase in prefusion pressure associated with intrarenal infusion of angiotensin I suggested conversion of the peptide to angiotensin II within the kidney. Basal renin secretion and the stimulatory response to isoprenaline were significantly suppressed by angiotensin I. The converting enzyme inhibitor SQ 20,881, infused at 1,600 X dose of angiotensin I, partially reversed the vasoconstrictor effect of angiotensin I without altering the degree of suppression of renin secretion.