Prostaglandin synthesis associated with renal allograft rejection in the dog

Vasospasm and intrarenal thrombosis are characteristics of acute renal allograft rejection. A possible mediator of these phenomena is thromboxane A2. Single kidneys were exchanged between nonimmunosuppressed mongrel dogs. At intervals after transplantation, rejecting and normal kidneys were removed and slices of cortex and medulla were prepared for incubation. The in vitro release of thromboxane B2 (TxB2), prostaglandin E2 (PGE2), and 6-keto-prostaglandin F1a (6-keto-PGF1 alpha) into the incubation media was measured by radioimmunoassay. Within 72 hr of transplantation the cortex of rejecting kidneys synthesized 10 to 30 times as much PGE2 and TxB2 as normal controls. A similar increase was not observed for 6-keto-PGF1 alpha synthesis. In the medulla there was a selective reduction in 6-keto-PGF1 alpha production within five days of transplantation. In both cortex and medulla there was a significant increase in the ratio of TxB2 to 6-keto-PGF1 alpha production. Reversal of the normal TxB2:6-keto-PGF1 alpha ratio could induce the widespread intrarenal thrombosis and vasospasm that characterizes acute renal allograft rejection.