Sar1-leu8-angiotensin II reverses the effects of captopril on renal function in rats

In Inactin-anaesthetized rats inhibition of angiotensin converting enzyme by captopril resulted in a small decrease in mean arterial blood pressure accompanied by increases in the rates of glomerular filtration, water and electrolyte excretion. Infusion (100 pmol/min) of sar1-leu8-angiotensin II (sar1-leu8-AII) during continuing converting enzyme blockade reversed these changes in renal function but had no effect on arterial blood pressure. The data indicate that sar1-leu8-AII has partial agonist activity in the kidney although it acts as an antagonist of AII in the systemic circulation. This supports the proposal that angiotensin receptors within the kidney differ from those in the peripheral circulation.