Thromboxane B2 and Prostaglandin E2 in the Rat Kidney with Unilateral Ureteral Obstruction

The production of prostaglandin E2- (PGE2) like and thromboxane A2-(TXA2) like substances is increased after release of unilateral ureteral obstruction (UUO) for 3 days in the isolated perfused rabbit kidney. It has been postulated that this increase in TXA2 biosynthesis might contribute to the development of vasoconstriction in the obstructed kidney. In the present studies, the production of TXA2 and PGE2 in the kidney was further investigated in rats after UUO for 2-18 h. Radioimmunoassay was used to determine thromboxane B2 (TXB2), a chemically stable metabolite of TXA2, and PGE2 production during the incubation of renal slices in vitro. Unlike previous studies, an increase in TXB2 and PGE2 production was demonstrable in the obstructed kidney even in the absence of pharmacological stimulation by bradykinin or angiotensin II. The effect of UUO on prostaglandin production differed in the different anatomical parts of the kidney. In the papilla, production of both TXB2 and PGE2 was increased in the obstructed kidney. In the cortex, however, UUO had a stimulatory effect only on TXB2 production but not on PGE2 production. The increase in TXB2 and PGE2 production was demonstrable as early a 2 h (tested) after ureteral obstruction. Prolongation of ureteral obstruction for 18 h diminished the stimulatory effect of UUO on PGE2 production but not on TXB2 production.