Angiotensin blockade in studies of the feedback control of renin release in rats and rabbits.
1. In rabbits actively immunized against angiotensin II (AII), the appearance of anti-AII antibodies was associated with a rise in plasma renin activity (PRA), which did not occur in mock-immunized controls. 2. In conscious rabbits, infusion of the angiotensin inhibitor, Sar1-Ala8-angiotensin II (P-113), at rates of 0.055, 0.22 or 1.1 nmol min-1 kg-1 into the renal artery, caused dose-related increases in arterial PRA and renal arteriovenous PRA difference. Renal blood flow fell with the high dose, but not with the low or medium doses. A fall in arterial pressure, asynchronous with peak renin secretion, accompanied the medium- and high-dose infusions. 3. Intravenous infusion of inhibitor P-113, 5.5 nmol min-1 kg-1, into anaesthetized rats produced highly significant increases in PRA and plasma renin concentration without reduction in arterial pressure. There were no changes in PRA or plasma renin concentration in saline-infused control rats. 4. These findings suggest that AII blockade interrupts a negative feedback loop controlling renin secretion.
D000804:Angiotensin II / Q000031:analogs & derivatives* / Q000276:immunology*; D000818:Animals; D000906:Antibodies; D001794:Blood Pressure / Q000187:drug effects; D005246:Feedback; D007668:Kidney / Q000098:blood supply; D008297:Male; D011817:Rabbits; D051381:Rats; D012039:Regional Blood Flow; D012083:Renin / Q000378:metabolism*; D012504:Saralasin / Q000494:pharmacology*
D000906:Antibodies; D000804:Angiotensin II; D012083:Renin; D012504:Saralasin