Role of angiotensin in normal blood pressure regulation

Summary Antiangiotensin II plasma induced transitory hypotension in rats when 0.2 ml was injected intravenously in normal males (either awake or anaesthetized), into binephrectomized females or into some males which had been nephrectomized 18–22 or 42–53 hours previously. Antiangiotensin II did not affect the blood pressure of male rats when given between 24 and 26 hours after nephrectomy. Antiangiotensin resulted in a 10–200 fold increase in the dose of angiotensin required to produce a measurable change in blood pressure, and also significantly reduced reactivity to l-noradrenaline.A remaining plasma renin activity was constantly found in binephrectomized females and in most of binephrectomized males. Plasma renin activity was significantly higher in the former than in the latter. It is concluded that angiotensin plays a role in the maintanance of blood pressure, in normal rats, in binephrectomized females and in some binephrectomized males.This work was supported by Grant 67-00-517 from D.G.R.S.T. (Délégation Générale à la Recherche Scientifique et Technique).This study was presented in part at the third Annual Meeting of the European Society for clinical Investigation, Scheveningen, Holland, April 26th 1969, and at the National Meeting of the American Federation for clinical Research, Atlantic City, N.J., U.S.A., May 4th 1969.