Opposition of the vasopressin-induced vasoconstriction in the isolated perfused rat kidney by some prostaglandins.

PGE2 can vasoconstrict or vasodilate the isolated Krebs-perfused rat kidney depending on the tone of the renal vasculature. Thus, it is weakly constrictor (thres-hold 5-10 ng bolus dose) in the perfused kidney whose perfusion pressure is 47 +/- 2 SD mmHg (n = 6), but becomes a vasodilator (threshold approximately 10 pg) in the kidney whose perfusion pressure has been raised to 73 +/- 6 SD mmHg (n = 6) or 121 +/- 8 SD mmHg (n = 6) through constant infusion of Vasopressin (0.1 and 0.25 mU/ml respectively. PGE1 was equally effective as PGE2 while other PGs, I2, I1, and 6-keto E1, were less effective in opposing vasoconstriction. PGF2 alpha was inactive up to a dose of 10 ng.