Responses of plasma renin to sodium load in two types of experimental renal hypertension.

A sodium-rich diet was given 20 rabbits with 2-kidney hypertension (clipping of one renal artery with an intact contralateral kidney), 19 rabbits with 1-kidney hypertension (clipping of one renal artery with contralateral nephrectomy), and 13 normal rabbits. Sodium content of the diet was twice as much as the regular diet. The sodium load was started 10 weeks after clipping of the renal artery and lasted for 2 weeks. During the sodium load blood pressure did not show any significant changes but hematocrit was reduced in all 3 groups. Plasma renin activity (PRA) was clearly suppressed in 10 of 19 animals with 1-kidney hypertension and in 6 of 13 normal animals, but only in 4 of 20 animals with 2-kidney hypertension (p less than 0.04). The results indicate that PRA was more easily suppressed in animals with 1-kidney hypertension than in those with 2-kidney hypertension by a sodium-rich diet and the suppressive response is not associated with alterations in blood pressure.