Changes of Blood Pressure, Renin and Aldosterone Secretions by Angiotensin II

Abstract

1-sareosine, 8-isoleucine angiotensin II (sar1, ile8-A II), was infused intravenously in 68 subjects with hypertensive, body fluid and electrolyte disorders and changes of blood pressure (BP), plasma renin activity (PRA) and plasma aldosterone concentration (PAC) were studied. Most low-renin subjects showed elevation of BP and PAC and reduction of PRA. Four of 10 high-renin, hypertensive subjects showed reduction of BP and PRA. Many high-renin, normotensive subjects showed elevation of PRA and more or less reduction of PAC. Reduction of BP was less predictable. Changes of BP, PRA and PAC of normoreninemic subjects were variable. Subjects with Bartter's syndrome and renal tubular acidosis showed a significant reduction of BP indicating subclinical volume deficit. Marked elevation of BP was observed in subjects with Cushing's syndrome and hypertensive subjects with pheochromocytoma. Failure of inducing BP reduction in many subjects with renovascular hypertension presents a problem as a means of screening for such patients. From data of BP, PRA and PAC of subjects with both extremes of PRA, it was inferred that sar1, ile8-A II is both agonistic and antagonistic at 3 sites of A II, i.e., BP, PRA and PAC in man. Factors other than renin and angiotensin appeared to be involved in hypertension seen in Cushing syndrome and pheochromocytoma.