EXPERIMENTAL AND CLINICAL STUDIES ON HYPERTENSION

Abstract

I. Relationship between RBF and Blood Pressure in Experimental Renal Hypertension:
In order to clarify the significance of renal ischemia in experimental renal hypertension, 11 dogs subjected to the Goldblatt's operation were followed for about 6 months, during which blood pressure and RBF were measured simultaneously, and then the following conclusions were obtained:
1. To produce the sustained elevation of blood pressure in dogs subjected to the Goldblatt's operation, it is necessary PBF to be reduced less than at least 80% compared to the preoperative levels.
2. In the course of time, there was a certain tendency for RBF to approach the initial level, but the elevated blood pressure continued approximately its high levels.
II. Demonstration of Pressor Substances from Renal Venous Blood in Essential Hypertension.
To Know whether or not pressor substances are present in the blood of the patient of essential hypertension is of the utmost importance. A series of experiments was undertaken, therefore, in an attempt to demonstrate their presence, and the following results were obtained:
1. In the extracts from 8 of 19 hypertensive patients, pressor effects were found. Their RBF showed reduction under 50% compared to normal ones.
2. In the extracts from 5 normal individuals these pressor effects were absent.
III. In conclusion, although depression of RBF under certain level is necessary, for the production of experimental renal hypertension the way in which essential hypertension is initiated in man may not involve the kidney. It is suggested that some factors other than the kidney probably participate in early essential hypertension and late stage of experimental renal hypertension. Following the reduction of RBF in essential hypertension, however, the ischemic kidneys liberate pressor substances into the circulation, and the kidney may play a role as one mediator of hypertension.