Intrarenal Distribution of Blood Flow in the Transplanted Dog Kidney: Effect of Denervation and Rejection*

Abstract

Serial measurements of intrarenal distribution of blood flow have been recorded in anesthetized dogs with the ¹³³xenon “washout” technique. The results showed that normal kidneys redistributed their blood flow after laparotomy and mobilization of the kidney. This alteration consisted of a diminution in percentage of total renal blood flow supplied to the fastest flowing component, and a diminution of renal mass supplied by that component. This effect lasted for as long as 7 days. Thereafter, the blood flow distribution remained stable. Autotransplanted kidneys had a stable distribution of blood flow between 0 and 77 days after operation, the values being identical with the stable normal kidney. Homotransplanted kidneys had the same intrarenal distribution of blood flow after operation as the autotransplanted kidneys. Whereas the intrarenal distribution of blood flow of the autotransplanted kidneys remained stable, a redistribution occurred in the homotransplanted kidneys as rejection progressed. This phenomenon occurred before marked elevation of blood urea nitrogen. The redistribution was due to a decrease in percentage of blood flow supplied to the fastest flowing component, and a relative reduction of tissue mass perfused by this component. Radioautography of the kidneys before rejection demonstrated that the cortex was homogeneously perfused by the fastest flowing component of blood flow. As rejection progressed, a reduced area of cortex was perfused by this component. Terminally, the fastest flowing component was located in the outer medulla. It is suggested that the reduction in cortical blood flow produced by immunological mechanisms may play a prominent role in the ensuing renal failure.