Release of prostaglandins during reversal of one-kidney, but not two-kidney, one clip hypertension in the rat.

Changes in systolic blood pressure and urinary excretion of PGE2 and 6-keto PGF1 alpha 24 h after removing the renal artery clip were compared in one-kidney and two-kidney, one clip Goldblatt hypertension in the rat. Unclipping the one-kidney rat returned blood pressure to normotensive levels within 24 h and was associated with a substantial increase in urinary PGE2 and 6-keto PGF1 alpha. Although hypertension was also completely reversed in the two-kidney model there was no significant change in urinary prostaglandin excretion. Prior treatment with indomethacin (6.0 mg/kg) markedly reduced urinary prostaglandins after clip removal in both forms of hypertension but attenuated the fall in blood pressure in the one-kidney model only. There were no significant changes in urinary kallikrein activity following unclipping. It is suggested that in the one-kidney, one clip rat prostaglandins are released as the result of exposing the unclipped kidney to elevated arterial pressure and that these contribute to the subsequent fall in blood pressure.