Prostaglandin-mediated hyperemia and renin-mediated hypertension during acute ureteral obstruction.

Acute elevation of ureteral pressure to 100 mm Hg in anesthetized dogs (n=7) resulted in an increase (P less than 0.005) in systemic blood pressure form 151 +/- 7 to 163 +/- 7 mm Hg, a transient (approximately 15 min) increase (P less than 0.05) in renal blood flow from 413 +/- 27 to 465 +/- 27 ml/min and a rise (P less than 0.05) in plasma renin activity from 6.0 +/- 1.6 to 10.3 +/- 2.1 ng/ml/hr. Pretreatment with a competitive inhibitor of angiotensin II, i.e. sar1gly8AII, abolished the hypertensive response to acute ureteral obstruction, and pretreatment with 2 mg/kg of either indomethacin (n=6) or meclofenamate (n=3), 15 min before obstruction, prevented the hyperemic response. These results suggest that acute ureteral obstruction leads to hypertension via activation of the renin-angiotensin system and hyperemia via a prostaglandin-initiated mechanism.