The experimental observation that led to discovery of angiotensin. 1939 Buenos Aires, Argentina.

This article is a short story of the work done by our group in Dr. Bernardo Houssay's larx> ratories in Buenos Aires 50 years ago that led to the discovery of angiotensin. In 1934 I was 23 years old and a student at the Faculty of Medicine of Buenos Aires University. I was paying for my studies by working as an undergraduate assistant teaching physiology to medical students at the "Instituto de Fisiologia" directed by Dr. Houssay. At that time, the Instituto de Fisiologfa was very active in various fields of research, such as carbohydrate metabolism and diabetes, cardiology, endocrinology, and others. To acquire a medical degree, I had to present a thesis that had to be approved by a special jury. I asked Dr. Houssay to supervise my doctoral thesis. He suggested experimental renal hypertension as the subject of my thesis. Attempts to induce sustained renal hypertension in laboratory animals had failed despite the different techniques devised such as reduction of renal parenchyma, occlusion of branches of the renal arteries, irradiation of the kidneys with x-rays, passive congestion of the kidney by venous obstruction, and many others. Conflicting results were published by various investigators. An initial rise of the blood pressure followed some of these procedures, but the rise was short-lived and prevented the study of the mechanisms involved. Sustained neurogenic hypertension, however, had already been induced by Koch and Mies in 1929 by the removal of the carotid and sinus nerves. While I was striving to induce arterial hypertension in rats by burning the cortex of the kidneys and facing problems with the measurement of the blood pressure, I came across the paper published by Goldblatt and coworkers in 1934. They showed that the reduction of the blood flow through the kidneys induced permanent hypertension in dogs. The introduction of a reliable method to induce permanent renal hyper-