ROLE OF THE NATIVE KIDNEY IN EXPERIMENTAL POSTTRANSPLANTATION HYPERTENSION

In experimental renal transplantation studies using several animal mod els of primary hypertension, including stroke-prone spontaneously hype rtensive rats (SHRSP) and their normotensive Wistar-Kyoto controls (WK Y), single transplanted kidneys from genetically hypertensive but not normotensive donors elicited post-transplantation hypertension in bila terally nephrectomized genetically normotensive recipients. The underl ying mechanisms are presently unclear. The present study was designed to investigate the effects of a remaining native kidney on post-transp lantation blood pressure, plasma renin activity and plasma angiotensin II concentration in (WKYxSHRSP) F-1 hybrid recipients of a WKY or SHR SP kidney. The presence of a native kidney markedly reduced, but did n ot prevent, post-transplantation hypertension in recipients of an SHRS P kidney. WKY kidney grafts did not significantly alter blood pressure in bilaterally or unilaterally nephrectomized recipients. Plasma reni n activity was lower in bilaterally than in unilaterally nephrectomize d recipients, regardless of the source of the graft. The plasma angiot ensin II concentration was similar in all groups. Renal graft function as assessed by (99m)technetium-mercaptoacetyltriglycine scintigraphy was well preserved. These data suggest that post-transplantation hyper tension in recipients of an SHRSP kidney may be partly due to the fail ure of the graft to eliminate a hypertensinogenic substance or to prod uce a blood pressure lowering agent.