Abnormalities of vascular wall sodium content in dogs with benign and malignant renal hypertension.

The water and sodium content of the saphenous vein was measured in 26 dogs with one-kidney, one wrapped hypertension. For comparison, the same measurements were performed on the contralateral saphenous vein which was removed prior to the induction of hypertension. Malignant hypertension characterized by blindness and a rise in plasma renin activity, developed in 10 dogs. The course of hypertension in the remaining 16 dogs was benign. In benign hypertension, the water and sodium content of the saphenous vein was increased. In contrast, the water content of the saphenous vein was unchanged and its sodium content fell in dogs with malignant hypertension. The dogs with malignant hypertension had a greater sodium content of the saphenous vein prior to the induction of hypertension than the dogs with benign hypertension. The findings indicate that the loss of body water and sodium that has been described in malignant hypertension also affects the composition of blood vessels. The sodium content of blood vessels may be a predictor of the dog's response to a hypertension-producing stimulus.