Analysis of Angiotensin II Mediated COX-2 Downregulation in Angiotensin II- or Aldosterone-Infused Hypertensive Rat

Abstract

The renin-angiotensin cascade plays an important role in blood pressure control and sodium homeostasis. This study investigated whether cyclooxygenase-2 expression is regulated in the kidney, in an angiotensin II- and aldosterone-induced hypertension model. For this purpose, we treated male Sprague-Dawley rats (n=8 per group) with angiotensin II (9 mg/h, subcutaneously) for 14 d and aldosterone (0.75 mg/h, subcutaneously) for 42 d. Systolic blood pressure was significantly increased by angiotensin II (p<0.001) and by aldosterone (p<0.001). We found that angiotensin II downregulated cyclooxygenase-2 protein in the kidney cortex, whereas aldosterone showed no effect. These results indicate that angiotensin II may act directly to inhibit kidney cortex cyclooxygenase-2 protein expression, rather than acting via stimulation of aldosterone.