Abstract
Summary and Conclusions
The renin-angiotensin system was studied in experimental renal hypertension produced by ligation of the poles of the left kidney followed by contralateral nephrectomy. Plasma renin concentration was the same in hypertensive and controls animals. The plasma concentration of renin substrate was lower and that of angiotensin I converting enzyme was higher in hypertensive animals.
The juxtaglomerular index decreased in the medial zone of the kidney, while heavily granulated areas appeared in the poles. Ligated kidneys of rats that remained normo-tensive showed juxtaglomerular indices intermediate between the control and the hypertensive rats. Differences in renal renin content between the groups correspond to those for the juxtaglomerular index, but were smaller.
No differences between the experimental groups were observed in iso-renin content in the brain; however, in all animals with ligated kidney poles, hypertensive or normo-tensive, there was a tendency for iso-renin in the adrenals, left ventricular myocardium, and especially aorta to be lower than in controls.
The role played by the changes of the renin-angiotensin system, in this kind of renal hypertension, remains to be elucidated.
These results suggest similarities between hypertension produced by compression of the kidney and hypertension produced by partial occlusion of the renal artery. Furthermore, when the kidney is compressed in this way, the medial zone behaves like the contra-lateral kidney in two-kidney Goldblatt hypertension.
The authors thank Miss L. Laporte and Mrs. I. Grimal for the technical assistance, and Mrs. M. Myette for secretarial assistance.
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