ROLE OF THE RENAL MEDULLA IN ADRENOCORTICOTROPIN-INDUCED HYPERTENSION IN RATS

Objectives: The mechanism of hypertension induced by adrenocorticotrophin (ACTH) remains unclear. The antihypertensive renomedullary lipids are vasodilators and it has been proposed that a deficiency of these lipids may contribute to the hypertension produced by destruction of the renal papilla. The aim of the present work was to study ACTH hypertension in both control and chemically renomedullectomized rats. Methods: Renomedullectomy was produced by single intraperitoneal injection of 2-bromoethylamine (BEA) at 400 mg/kg. Results: BEA-treated rats all developed increases in water intake and urine volume, with loss of papillae and medullary and cortical fibrosis. There was a significant correlation between papillary ablation and sytolic blood pressure (SBP). SBP in renomedullectomized rats was higher after ACTH than sham injection, and higher than after ACTH injection in intact rats. Conclusion: Chemical renomedullectomy with BEA did not block or attenuate the onset or magnitude of ACTH hypertension in the rat.