1961 Volume 3 Issue 4 Pages 445-450
There has been a large body of reports on the experimental renal hypertension. Recently, Muirhead reported that the hypertension could be prevented by the autoexplantation of renal tissue in the bilrterally nephrectomized dogs. His observation suggests that antihypertensive substances may be produced by the medullary tissue of healthy Kidneys. The study was carried out in dogs to further investigate this concept, by utilizing different techniques. Mongrel dogs, weighing 12-22 kg, were used for this experiment . A bilateral nephrectomy was performed in 2 dogs. The ureters were both ligated in 6 dogs. In 2 dogs was bilateral uretro-venous anastomosis done. Parenteral administration of the homogenate of the total Kidney following bilateral nephrectomy, in 2 dogs, the administration of the cortical homogenate following bilateral nephrectomy in 1 dog, and the administration of the medullary homogenate following bilateral nephrectomy in 2 dogs were also perfor med. These dogs were expired in a typical uremic state approximately 7 days postoperatively. A mean arterial pressure was measured daily by a mercury manometer until demise. The dogs with a bilateral nephrectomy demonstrated progressive and profound rise in arterial pressure with a daily increment of 14.3 mmHg. Blood pressure in the group of dogs with a bilateral ureter ligation was also rised progressively but much more slowly with a daily increment of only 8.1 mmHg. No significant alteration in blood pressure was noted in the dogs with a bilateral uretrovenous anastomosis during the experiment. There was little rise in blood pressure following the administration of homogenates of the total Kidney as well as the uretro-venous anastomosis. The elevation of blood pressure was marked in dogs with the intraperitoneal administration of the cortical homogenate, whereas there was pertically no elevation in dogs with the administration of the medullary homogenate. The above findings agree with Muirhead's observation and support the thought that an alive renal tissue mass plays a vital role in the maintenance of normotensive state, probably by producing antihypertensive substances.
