Aldosterone biosynthesis and excretion during the development of two types of experimental hypertension, 1976

Urine and plasma aldosterone levels were determined in rats during the development of renovascular and salt-induced hypertension. A systolic blood pressure above 150 mm Eg was used as an index of the hypertensive state. This level was achieved in approximately 30 days in both systems. Renovascular hypertension was produced by removing the right kidney and a 0.3 nun silver clip was placed around the renal artery of the left kidney. Salt-induced hypertension was produced by substituting 1.5% saline for drinking water. Blood pressures were taken by the tail-cuff method and aldosterone was determined by radioimmunossay (New England Nuclear protocol). Plasma and urine samples from both experimental groups were collected at 10, 20, and 30-day periods. The aldosterone levels of the renovascular hypertensive rats were not significantly different from the controls as the blood pressure increased. In the salt-induced hypertensive rats the aldosterone levels decreased as the blood pressure increased. This suggests that aldosterone is not a primary causative factor for the production of hypertension in these two systems