Chemical renal medullectomy and experimental hypertension

The possible vasodepressor role of the renal medulla was studied by chemical medullectomy (i.v. bromoethylamine hydrobromide) in rats. A significant increase in blood pressure (BP) was observed 10 weeks after injection which related to the increase in urinary volume and decrease in urinary prostaglandin E2 (PGE2) in medullectomised rats, but not to plasma renin concentration (PRC). Creatinine clearance was unchanged. The differences between control and medullary damaged rats were maintained over a wide range of sodium intakes although the patterns of response were similar in the two groups. The increase in BP observed following renal medullectomy is likely to be secondary to a reduction in interstitial cell function.