RÔLE OF THE KIDNEY IN PATHOGENESIS OF HYPERTENSION AS DETERMINED BY A STUDY OF THE EFFECTS OF BILATERAL NEPHRECTOMY AND OTHER EXPERIMENTAL PROCEDURES ON THE BLOOD PRESSURE OF THE DOG

Abstract

The effect of the following procedures on the mean blood pressure of the dog was detd.: (1) bilateral nephrectomy; (2) bilateral ligation of both ureters; (3) ligation of one ureter, the other remaining intact; (4) implantation of one ureter into the abdominal vena cava with removal of the contralateral kidney. The period of survival of the animals deprived of renal excretory function was prolonged by maintaining them on an electrolyte-free diet and by application of an artificial kidney at intervals of 4-5 days. The blood pressure of the nephrectomized animals gradually rose to hypertensive levels and at autopsy revealed the pathological findings of malignant hypertension. Ligation of the ureters resulted only in a temporary rise in blood pressure. If the contralateral kidney was removed following the return of the blood pressure to normal, no elevation in blood pressure occurred. Likewise, in animals with one ureter implanted in the small intestine or into the vena cava and the contralateral kidney removed, no hypertension resulted. It is concluded that nephrectomy results in hypertension and that the presence of intact renal tissue is essential for the maintenance of the normotensive state. The present studies offer direct evidence for the view that the kidney normally, in addition to its excretory function, also exerts a function which is concerned in the maintenance of normal blood pressure levels. Hypertension of renal origin according to this view is not due to the liberation of a pressor agent, but results from a failure of this activity of the kidney.