The objectives of the present study were to test the hypothesis that vascular angiotensin II (AII) generation may be negatively regulated by circulating AII in Wistar-Kyoto rats (WKY) and spontaneously hypertensive rats (SHR), and to clarify the role of this vascular AII in the sustained hypertension seen in SHR following nephrectomy. The mesenteric arteries from kidney-intact and nephrectomised WKY and SHR were perfused, and the level of AII released into the perfusate were measured. The effects of CV-11974, a newly developed nonpeptide AII receptor antagonist, on AII release were examined to investigate the existence of a local feedback system in the blood vessels. Nephrectomy augmented vascular AII release both in WKY and SHR despite the reduction in circulating AII. CV-11974 significantly increased AII release from the mesenteric arteries of kidney-intact rats. There were no significant differences in these responses between WKY and SHR. These results suggest that WKY and SHR share a potent pathway for producing vascular AII in response to the withdrawal of circulating AII, although this pathway is not responsible for the sustained hypertension seen in SHR after nephrectomy.