Zimmerman BG, Birt PC
Greater hypotension during renin than ACE-inhibition associated with decresed plasma AI but not AII
12th Annual ASH Meeting
Am J Hypertens (Apr) 10:170A 1997

The purpose of this study was to compare the effects of a renin inhibitor -- EMD 58265 (EMD) -- and a an ACEI -- enalaprilat, on the arterial blood pressure (BP) and renal blood flow (RBF).

The experimental design is not entirely spelled out in the abstract but inferred to be as follows: Seven New Zealand White rabbits (age and sex not specified) were anesthetized with sodium pentobarbital and measurements were obtained at the begining of the experiment and after respective sequential administrations of enalaprilat (ACEI) and EMD. Two of the rabbits were normotensive at the begining of the experiment and five were two-kidney one-clip hypertensives. Data were pooled from the seven rabbits.

Results:
ControlEnalaprilatEMD
BP (mm Hg) 107±12 89±9** 75±10*
RBF (ml/min) 37±6 40±10 32±4
AI (pg/ml) 1007±676 1923±865 32±4*
AII (pg/ml) 381±189 222±145** 440±354

Comment: Renin inhibition produced a significant reduction in blood pressure beyond that already accomplished by ACEI (P < 0.05). This in the face of doubling in the level of angiotensin II (AII) from the initial 51.8% reduction achieved by ACEI. This poses two problems:

1. It means that renin must have a regulatory effect on BP other than the well recognized effect mediated by the sequential generation of AI and AII.

2. It leaves one searching for an explanation for the incongruent elevation of AII following renin inhibition and almost complete elimination of AI.

Other problems not addressed in the abstract -- there are space limits after all -- are:

1. The fact that neither agent affected the RBF; in contrast with the results of others, which prompted this study ( Hollenberg et al , Hypertension 26:602-209, 1995).

2. More interesting even is the fact that results from normotensive and hypertensive animals were pooled. Does that mean that the results obtained in these were comparable to those obtained in normotensive ones thus legitimizing the pooling of data? If that was the case it would bear some elaboration on. (Samy S. Iskandar, MBBCh, PhD, Bowman Gray School of Medicine, Winston- Salem, NC)

To go back use the BACK button on your browser.
Otherwise click on the desired link to this article below:
12th Annual ASH Meeting
H: Drug therapy : ACE inhibitors