RENAL AMYLIN BINDING IN NORMOTENSIVE AND HYPERTENSIVE RATS - EFFECTS OF ANGIOTENSIN-CONVERTING ENZYME-INHIBITION WITH PERINDOPRIL

Objectives To investigate the effect of angiotensin converting enzyme inhibition with perindopril on the binding density of [I-125-rat amyli n in the renal cortex in normotensive Sprague-Dawley rats, renally abl ated hypertensive rats and spontaneously hypertensive rats, Design Spr ague-Dawley rats, renally ablated hypertensive rats and spontaneously hypertensive rats were administered either the angiotensin converting enzyme inhibitor perindopril or no treatment. Methods The density of [ I-125]-rat amylin binding was measured in the renal cortex using autor adiography in vitro, The systolic blood pressure was measured by indir ect tail-cuff plethysmography. The plasma renin activity was measured by radioimmunoassay. Results The density of [(125)]-amylin binding was reduced by approximately 50% in Sprague-Dawley and subtotally nephrec tomized Sprague-Dawley rats after treatment with perindopril, These ch anges were associated with a reduction in systolic blood pressure and an increase in plasma renin activity, In contrast, amylin binding in t he perindopril-treated spontaneously hypertensive rats was not reduced , despite the prevention of a rise in systolic blood pressure and an i ncrease in plasma renin activity, Conclusions These findings provide f urther evidence for the hypothesis that there is an association among renal amylin binding, the renin-angiotensin system and blood pressure for rats of the Sprague-Dawley strain, In contrast, the lack of an eff ect of angiotensin converting enzyme inhibition on renal amylin bindin g for rats of the spontaneously hypertensive rat strain is consistent with previous findings that the changes in amylin binding in rats of t his strain are not linked directly to the prevailing systemic blood pr essure but may be associated with a developmental abnormality in the k idney of these rats.