Hypertension, Vol 1, 624-630, Copyright © 1979 by American Heart Association
R Albertini, A Binia, Y Otsuka and OA Carretero
Previous studies have suggested that angiotensin II and sodium can act as
alternative mechanisms in maintaining high blood pressure in chronic
renovascular hypertension, In the present study, exchangeable sodium was
measured in rats in which angiotensin II has been confirmed or excluded as
the main cause of the hypertension. To determine the degree of
participation of angiotensin II in the maintenance of the high blood
pressure, we studied the mean blood pressure response to an angiotensin
antagonist (1-Sar-8-Ala-angiotensin II) and to a converting enzyme
inhibitor (SQ20,881). Rats with a decrease in blood pressure of less than
20 mm Hg, in response to both inhibitors, were classified as nonresponders;
those with a decrease of 20 mm Hg or more, as responders. Fifty percent of
the rats with two-kidney hypertension were nonresponders, and they had
lower blood pressure and plasma renin activity than the responders.
Further, these two-kidney, hypertensive, nonresponder rats had normal
exchangeable sodium. The two-kidney hypertensive responders, on the other
hand, had significantly higher exchangeable sodium than both the
two-kidney, hypertensive nonresponders and the two-kidney control rats.
These results suggest that angiotensin II and exchangeable sodium do not
play a major role in the maintenance of the high blood pressure in the
two-kidney hypertensive nonresponders. However, there appears to be an
abnormal relationship between renin and exchangeable sodium in the
two-kidney hypertensive responders that could contribute to the maintenance
of the hypertension.
ARTICLES
Exchangeable sodium in angiotensinogenic and nonangiotensinogenic renovascular hypertension