SUMMARY It has been suggested that in two-kidney, one clip hypertension, the undamped kidney (UK) actively contributes to hypertension by reducing its excretory ability in response to increased levels of Circulating angiotensin II. By exteriorizing the ureter to the dog's flank several weeks beforehand, we measured renal function directly from the UK of six chrogic renal hypertensive (> 3 weeks) and six normal dogs (ND).
IT HAS BEEN suggested that overactivity of the renin-angiotensin system in the acute phase of two-kidney, one clip hypertension depresses renal function in the undamped kidney, preventing diuresis and enhancing sodium and water retention.1 Whether these effects are still present during the chronic phase of renal hypertension continues to await clarification, due in part to technical limitations that have precluded evaluation of the function of the untouched kidney in conscious chronic
649hypertensive animals before and after blockade of the endogenous formation of angiotensin II (All). Technical difficulties impeding progress in this area of hypertension research were recently resolved in this laboratory, first by the development of a procedure that provides a reliable model of chronic two-kidney one clip hypertension in the dog* and, second, by implementation of a modified method of surgical diversion of the ureter that allows for unilateral renal function studies.3 Because these problems were circumvented, we are now able to report the changes in the function of the untouched kidney of dogs with chronic two-kidney, one clip hypertension both before and after acute blockade of the endogenous formation of angiotensin II with the converting enzyme inhibitor (CEI) SQ-20,881.
MethodsBefore and during the studies, 12 male mongrel dogs weighing 18-25 kg were fed a normal diet (Ken-L-Ration Biskit, The Quaker Oats Co., Chicago, Illinois) containing 60 mEq/day of sodium and 45 mEq/day of potassium; water was given ad libitum.