INHIBITORS OF THE RENIN-ANGIOTENSIN SYSTEM IN EXPERIMENTAL-HYPERTENSION, WITH A NOTE ON THE MEASUREMENT OF ANGIOTENSIN-I, ANGIOTENSIN-II AND ANGIOTENSIN-III DURING INFUSION OF CONVERTING-ENZYME INHIBITOR

1 Prolonged infusion (11 h) of both saralasin and angiotensin‐ converting enzyme inhibitor (SQ20881) gradually lowered BP in two‐ kidney hypertensive rats to levels similar to that in normotensive rats infused with dextrose. 2 Saralasin did not lower BP in DOCA‐salt hypertensive rats. 3 These observations support the notion that in chronic renal hypertension, angiotensin II may maintain hypertension by a slowly developing action. 4 Plasma angiotensin II in rats infused with SQ20881 was suppressed relative to renin, but was not eliminated. 5 Chromatography of angiotensin II extracts from dogs infused with converting enzyme inhibitor (SQ14,225) showed that the very high levels of angiotensin I achieved after treatment with SQ14,225 can lead to falsely high estimated angiotensin II levels as a result of angiotensin I cross‐reacting with the angiotensin II assay. 1979 The British Pharmacological Society